R. A. T. 7 mouse? Is it good?

You won't need the DPI, but the customizability is potentially good and if you take your time to set it up, you might be able to get a perfect fit. However, it is quite heavy and its sensor is prone to the z-axis issue and is more picky about the mousepad than most other common "gaming grade" sensors.

You might need the DPI, I play FPS at 4000...

I have the R.A.T 7 and it's a good mouse, my only gripe is it has a very slight wobble when you rearrange the parts of the mouse into certain positions.

Owned one previously, my main complaint is that it's a heavy mouse, even when unweighted.
I'm used to Razer's lightweight mice, and although the RAT 7 was very customizeable, it made my wrist tired after an hour or so of gaming.

I sold it, and bought a used/refurbed Razer Imperator for cheap, and bought a CM Storm Xornet that went on sale as a backup

I have it as well and I am more than pleased especially with the customization you have and I love the thumb wheel. Why I love the thumb wheel? In game you can have it clockwise giving you on of your weapons and anti-clockwise the other one but the best thing is in browsing, having 10 tabs open in chrome I go from on to the other with that wheel and it's just way too useful and fast. It can be used with endless possibilities but once you get used to it in everyday tasks you just can't get by without it. Also the sniper button is EXTREMELY useful with FPS especially if you snipe but even in normal situations I use it and I'm extremely accurate. As of weight I don't find it heavy at all, actually I put all the weights on it because I wanted it heavier and even now I don't find it heavy but I believe this has to do exclusively with personal preference.As of build quality many said that the plastic feel to it is bad I personally love it.

My complaints are 3:

1) The bigger palm grip becomes a bit loose when put on the edge.

2) Left click stopped clicking correctly after a year. This can be fixed by opening the mouse and adjusting the click spring but it's a bit of a pain in the bottom, I did it and broke a little bit of plastic that was holding the thumb rest in total place but that was entirely my fault for not being careful. I fixed but it's a bit of a pain in the bottom. As far as I know this happens to most mice out there except really high quality ones (some Logitech models).

3) The software that you make profiles doesn't have the feature of auto loading a profile when the game is launched (something that my Logitech G19 keyboard has) but that is really minor to be honest.

As of mousepad I use the Razer Goliathus α Control Edition (smoother) and it's working great.

My personal setup is 1875 DPI on the mouse, low in-game sensitivity, 84% sniper button smoothness, huge mousepad, palm-grabbing that sucker and using my whole arm from the elbow down for ultimate control and accuracy.

I don't know how people can stand moving their arm whilst using the mouse, at 4000DPI I have to move my hand ~1cm to get from one side of the screen to the other.

Also I forgot about the palm grips, however for me all of them wobble when they are at the last notch.

Also the thumb rest can move slightly if you squeeze the mouse hard enough, despite tightening to screw as far as I could.

The sensor in that mouse is crap - google Philips Twin Eye. It's still fairly good, if you compare it to mice just 3-4 years ago, but even the cheapest gaming mice of today will perform better.

The sensor is not bad on the right surface, at least doesn´t have acceleration like the avago counterpart.

My complain is about the shape and button placement, the sniper button is just unusable due to the position, side buttons (back and forward) are just too hard to press, they just **** your aim if pressed.
Plus, It´s heavy, expensive and not comfortable (for me at least) because it has less hand-contact surface than regular mice so is like holding a weird contraption rather than a curvy ergonomic soft shell.