Athletic supporters are never truly comfortable, but the Basix comes darn close. This is a big step ahead of your traditional jocks traps, and stays in place really well. Not to mention it gives you a little edge in locker room etiquette so you don't have to walk around in the buff or with nothing but a jock on.  

These are very comfortable and after awhile you don't notice it's on. The material is very stretchy and the cup that comes with it is very comfortable (well, as comfortable as a cup can be). I read the review below where it ripped and I think I see the source of that problem. When you get these, just look on the inside. You'll see the left over string hanging there. Just tie it up in a bunch of square knots and you're good to go! I've used these 3 times now (and washed them) with no seam problems to report. Like the review says below, if you sew (bachelor's survival skill 101) you'll be just fine. I'd have given these a 5-star rating if it weren't for this little flaw. Two thumbs up on these. Very comfortable cup.  

Wearing groin protection while grappling can be uncomfortable. These shorts keep everything in place and can be worn comfortably for long periods of time.  

Having played football in school and mountain biking as a hobby, I have grown fond of compression shorts for many reasons. They keep your muscles in place during all sorts of rigorous and repetitive actions to increase performance and protect sensitive nerves (great at keeping that sciatic nerve from pinching).
These shorts go a step further -- they combine compression shorts with jockstrap/cup. The X system provides *comfortable* support and keeps everything in place.
The best thing about these shorts really is the comfort they provide. They do not limit movement, they wick away moisture, and are made of a highly breathable, strong, yet flexible and soft material.
You can't beat the combination of protection & comfort in this package. They are just as comfortable with the cup as they are without or without the cup, which by the way is worthy of a great review itself.
If you are in the market for a new cup, jock strap or pair of compression shorts, buy these. You get them all in one package, with cup usage optional based on use.
As a side note, I've used these while biking (due to forgetting to wash my biking shorts) and despite the lack of rear padding they were extremely comfortable and performance far exceeded my expectations.

Buy them!  

I purchased these shorts in January and they are very comfortable, but after using them only a couple of times the mesh pocket that holds the cup in place has already ripped. My wife sewed them and there as good as new. I've been using them for over a month now and no more problems. These shorts are very comfortable and if you have someone that can sew I recommend these shorts.  

After using many different types of groin protection over the years, this is the most comfortable protection I have found so far, especially when having to wear it for long periods of time.  

The quality and the stitching on the shorts are great. They are light, breathe well, and don't limit movement. The cup is giant, though. Like twice the size of every other adult-sized cup I've ever owned. Luckily, you can take the included cup out and replace it with a normal one.  

After using several different styles of groin protection over the years, this is probably the most comfortable protection I have found, especially if required to wear for long periods of time.