UPDATE 4/26/2021: So this is a bit of a saga. I got so frustrated with M1 and M2 buttons and their weird feel, I returned my open box Burst Pro. About a week later I was at Microcenter and they had a Burst Pro on display. I picked it up on a whim and clicked the buttons. I noticed that the right click on the display mouse was light and crisp, almost like a Razer Viper, but slightly more hollow. The left click felt like I originally described; stiff, hollow, and dull.So that got me thinking, maybe they revised the clicks on later models? I still didn't want to pay full price though for something that seemed like I was going to be potentially disappointing. So I ordered a second open box Burst Pro from Amazon for $30. This one was listed as 'acceptable', but it was like new, just the box was beat up.In any case, I think I got lucky. The M1 and M2 on the second open box mouse were worlds better than the first mouse. They felt like the right click on the display version of the Burst Pro at Microcenter. So this leaves me with some questions. Are these mice really inconsistent during production to the point that M1 and M2 can be so vastly different from mouse to mouse? Or is this a revised version? I don't know. I know that the Viper went through some updates over time to improve their main clicks. Roccat could be doing the same thing, or they could just have really poor QC during manufacturing. Considering how solid the rest of the mouse is, I have a hard time believing it is a QC issue.In any case, this is my new main. The issue I had with it is resolved on this copy, and I love it. I went ahead and bumped it up to 5 stars.------------------------------------------------------------------------------------------------------------------------------This review is almost painful to type out. I want to love this mouse so bad. It could easily be my main, but it's let down by the mouse 1 and 2 buttons. Let me get to the good parts first.Pros:-Lightweight, this is huge! It's a midsize mouse, but it's soooo light-Great shape, it seems pretty safe for most grips. I fingertip most of the time, and it works great that way. My handsize is 19 cm x 10.8 cm. It's very comfy for longer play sessions.-Great cable! It's not a paracord, but it works really well. I don't feel the need for a bungee.-Good side buttons. Very snappy and responsive. They are also easy to hit. One of my main complaints with the Viper and Model O are the side buttons being either too recessed or too far forward. The Burst Pro gets it right.-Good materials. This is a sturdy mouse, despite its weight. Also, the materials feel really good, even when you get a little sweaty.-Amazing skates !!! This things slides around so good. You will not need to upgrade skates on this mouse at all. It also comes with a spare set in case you wear yours out or have to take off the originals for some reason.-Good scroll wheel. The scroll feel is slightly inconsistent, but its pretty good. Clicking is great.Cons:-M1 and M2 buttons. This is about the only thing wrong with this mouse, but its egregious. The buttons lack feedback, take a lot of pressure to depress, and feel hollow somehow. It is nice that they are optical so they will never double click. And they do not have any pre/post travel, which is great too. But they feel bad to press. This mouse needs a revision with new M1 and M2s, closer to the new Razer opticals at a minimum.-Not available in wireless. This mouse begs to be wireless. It's so good, and wireless would make it even better. If they could maintain the same weight, so much the better.I picked this mouse up for about $30 open-box, so I am not complaining too much. It just sucks that the M1 and M2 are so bad. It ruins an otherwise great mouse. Hopefully we see a Burst Pro V2 or a Burst Pro Wireless in the future with better clicks.