Just keep in mind that expensive doesn't always mean better.
I think the G19 is overpriced. The screen and macros are nice if you need them. Any keyboard at that price point should be mechanical though.
Aesthetics are subjective. I don't care for backlit and glowing peripherals on my desk...
Until you start outrunning it like me. I wouldn't have a problem recommending it to lower-mid sens players though since the perfect control speed is it's only real problem.
Intellimouse line is 400 DPI. It also has a max perfect control speed of 1.5 m/s so it's pretty limiting if you're a low-sensitivity player. It's easily beaten by the MX518, G400, and Deathadder in this regard.
Abyssus is designed for claw-grippers only. Jitter is hit or miss, the ones that jitter are picky about cloth pads.
Kinzu has one of the worst sensors known to man, I'd avoid it.
Imperator uses the Twin-Eye sensor, I'd also avoid that too. If you want the shape, get a MX518 or G400.
Run it at 500hz or more and it will raise perfect control speed to 1.55 m/s. Not stellar, but still better than at 125hz.
Even then, it's still pretty easy to hit that ceiling if you play low-sensitivity for long enough.
I mashed both of my hands on the keyboard and it seems like most, if not all the ones I pressed worked, including the combos you listed.
Filco tenkeyless NKRO.
If you want a light mouse, don't get a G500. They're still heavy without the weights if you compare it to something that's actually light like an Abyssus or Kinzu.
It's only able to keep up with 30 inches per second swipes? Probably not good for FPS if you're a medium sensitivity or lower player. I can hit the max perfect control speed of the Intellimouse line and it's capable of swipes twice as fast.
The G500 has inherent positive acceleration due to the ADNS-9500 sensor. It's around 5-10% and is inconsistent. This may or may not bother you and many people play fine with it, but I feel it should be known to potential buyers looking at it.
There have been reports of negative acceleration...
The Black Widow is produced for Razer by iONE, of course support would be provided by Razer though.
Go mechanical and never look back. I had a G15 before my Filco and I've not regretted it once.
You have to hold it at a slight angle and move the mouse up or down and it should do it. Seems like a hit or miss thing with certain cloth pads. This is at 450 DPI.
Otherwise, it works perfectly on my G-RF and I'm quite happy. No more negative accel from my 1.1. :D
I just picked myself up a standard Abyssus and I wish I did it sooner. It jitters on my Talent if I hold it at the wrong angle so I'm using my Zowie G-RF pad with it now.
I had one for a bit. I got rid of it because it didn't like cloth pads. If you want the same shape, get a Mionix Naos 3200. Same shape with a better sensor.
The 6Gv2 is probably your best bet. Built well as said and Cherry MX Black switches will last you for years. Also the heavier nature of the MX Black switches are more suited for gaming.