They work okay in general, designs are great(but no longer innovative) their build quality is as cheap as it gets, and I fully expect anything from them to fall apart in a year or two.
My old molten razer naga was my fav mouse from cata onward, but during WoD early tier, the weight inside broke loose and I had to dissassemble and found out the weight was held by just cheap plastic. It lasted for several years.
I've moved over to logitech, corsair, or plantronics for most gaming needs now.
Also, I didn't like their "always online" software array.
If they took some of the money from packaging and raised manufacturing standards, their stuff would be a lot longer lasting at least. Feels like lowest bidder build quality.
I wouldn't mind using a razer again, buy my last wireless naga chroma had issues where it would go dead after 20 seconds of non-movement and have to be "primed" by moving it a bit. Razer was no help on that one. I got the wired naga and it was okay, but in the end I didn't like the design because the keys were flat(unlike on my molten) and the logitech keys were canted so you could tell each on by feel, so I went that direction. It also was bigger and fit my hand a little better.
I have one of those cheap mice, red rose or whatever, mentioned in this this thread. Its hefty and works okay, but nothing stand out about it but the price. So far, the logitech mmo mouse has been my fav. I also love the logitech fps mouse, for overwatch. The clutch button and the layout are better. I feel that buttons being able to be told by "feel" is optimal, which is one major advantage of logitech currently, imho.
The logitech software has some issues, honestly, but it still works okay. The g910 mechanical keyboard has definitely been my fav ever. They also had the "best" wireless headset for under 100 bucks for a while, I think it was the g930. I no longer use it, since I'm back to high end wired, but I wore out several oem rechargable batteries in that rig and never had a problem until I got sick of wireless headsets.