If you are the guy that only wear normal jeans and look for some additional protection when you go on freeway, this thing will do.
If you already have riding jeans but feel like the knee protection is lacking, this thing will do.
If you wondering if you should spend money on these instead of a proper riding jeans, go buy riding jeans, these thing won't help you from the asphalt BBQing your butt.
That being said, these thing are pretty well made and seem pretty durable, I think they will stay in place in the event of a crash.
I ride sportbike, your knee bent a lot more than on other bikes. I feel like these thing are not made for us sportbike rider, it is either too loose or too tight. If I tighten it up as it supposed to be, it is too tight and grow uncomfortable, if I leave it loose, it won't help when I get down. Naked bike, ADV, Dual sport, Cruiser,... you guys will do fine.
The velcro on top can be improved, the hard velcro (male I think) face against your knee so don't wear these under your jeans (as if you can). The velcro can bite your skin or your sweatpants and scratch it up if that is how you wear on your ride.
The ventilation is not good, I feel little air coming into my knee so it can grow uncomfortably hot on 100F days. But if it is cold, this thing can act as a shield that deflect the air so less cold air go into your pants.
The bottom line of this thing is a beefed up skateboard knee guard for the street, it will work better than the kneeguard in any riding jeans if it stay in place which I think it will.

These knee pads are great for shorties like me, I'm 5'6" and short legged so typically the knee armor for bike pants sits around my shins. These offer decent protection with a hard(ish) plastic cover so you know its going to be stronger than the included stuff you get normally.
No noticeable airflow, if anything it makes ur pants breathe a little less because they'll be cinched tight at the knees.
They're quite comfortable but sometimes the straps will pinch behind the knees depending on how u do them up.
The plastic buckles sit on the inside, which don't really effect my FZ07 but if you're riding a sportbike im not sure if they're placed far enough back to keep from scratching your fairing. Your mileage may vary depending on riding style and bike application.
Exactly what i wanted out of the purchase, would definitely recommend for those after this kind of knee protection - knee dragging not recommended

What I was looking for:
* good protection (I like my knees)
* easy to put on/off (I need them for my daily commute and I don't want to add too much additional time to my suit-on routine)

These deliver that.

Summary: They are not pretty or inconspicuous (it's a large/wide black fabric guard with a huge ICON plastic logo) but offer good protection, stay comfortable in place and are quick to put on/off.

In detail:
- I was surprised at how big they are. Not that they run large to size, is that the apparatus is big. There is a lot of it.
The size SM/MD are 32 cm length X 24 cm (on the thigh end) and 32 cm on the calf end .
They wrap your leg nicely, not just the knee, but the sides too. I am 5"2 (158 cm, for us metric system people). The SM/MD fits just sligthly long (I'm used to things being longer than I need them to be), but they are flexible and adjust fine to my leg size and form.

- The body of the thing is fabric, so they will not retain the form you see on the pictures. That has it advantages: they bend and accommodate to your knee/leg.
The down side of that is that it makes them look sloppy, not an elegant streamlined look, but a bulky thing wrapped around your leg.

- The exterior fabric feels robust, so I hope it has good abrasion resistance (so far I have not tested it)

- The interior fabric is nice and soft. It's actually hydra-dry.

- Bonus: the quick-release buckles have a little fabric covering them, to prevent scratching your tank.

Buy protection that fits and is easy to use. If you don't, you will never have it on when the fall or slide occurs.

Most motorcycle safety equipment rots in the riders closet and is never worn due to its lack of comfort and ease of use.

You want safety equipment that is easy to use and quick to put on or when the fall or slide occurs and it will, you won't have it on~!

This product is great for everyday riding and easy to use.

Recently had a nasty wreck. Brain injury was the main focus but my knees and feet got pretty beat up. That was on track in full Alpinestars and Sidi Vertibra. I ride in Bull-it jeans with knee armor on the street but wanted real deal knee protection that is more likely to be in the right spot at the right time if the wrong thing happens. I'm satisfied. They fit ok under my Bull-its but over is better. I toss em on over regular jeans when I run short low speed errands across town (NYC). Your knees and feet are so vulnerable in any kind of get off. Protect them!

Fit seems right , extra layer of protection with a nice looking and good style.

Excellent quality and protection. Easy adjustment for a custom fit. Well worth the price.

The Icon Street Knee Guards are perfect for riders who prefer protection while riding, but do not have/want riding pants. They fit comfortably over your your jeans and have enough flexibility to wear during stops w/o needing to take them off. They do feel a little bulky, but it's nothing to worry about if you like your knees (the fact is that anything over your jeans is going to feel bulky...it's padding).

As for riding... I am on a Yamaha FZ-07, so my seating position is a little more upright than my super-sport counterparts. They're great if your bike is like mine, but I can't speak for a bike which has you in a more crouched riding position.

Style... I actually think they look kinda cool. Since I've had them, I've had a couple other riders ask me about them because they wanted more armor, but didn't like what was available in the market (knee sliders or MX-style knee/shin guards). I guess looking "cool" is more important than having knees that survive a crash, but who am I to judge? Bottom line, other riders seem to like them.

I would definitely buy if you need the protection, but don't have actual riding pants.

They are very low profile on me and my skinny legs. Not to bulky with a bit of flex to them. That being said I feel that they would hold up fantastically in the event of a spill. The impact area is a soft material so it would not be ideal for knee dragging or multiple direct impacts/slides, but for the price its hard to beat the added safety. The velcro and straps seem durable along with the double stitching these should hold up for a long time.

These street knee guards are a great solution to quickly and easily add protection when commuting. They allow me to have protection without having to change out of true riding pants at my destination. They are comfortable and have the added benefit of blocking the wind and keeping my knees warm. The flip side is they will be warm on hot days but I haven't found any type of armor that actually breathes. I can recommend these without reservation when you need/want protection without having to wear actual riding pants. I considered purchasing "over pants" but decided that these would be more versatile since they could be worn over my existing warm and cold weather pants to add the protection they lack.