Differences between Pure and Poker 2:
1. Pure is PCB mount, Poker 2 is plate mounted.
2. Pure has 6 mounting screws, Poker 2 has 5. So Poker 2 board will fit more cases, whereas the Pure needs ones with the extra screw otherwise it gets a bit bendy.
3. Pure Fn layout is different to Poker 2. I prefer the Pure layout, but the Poker 2 has a fully programmable Pn layout, which makes this kind of moot.
4. Pure has a short right shift and an extra 1x key on the shift row. Poker has standard ANSI layout. It's easier to find keycaps for Poker 2, but many sets do have an option for getting a short right shift. A lot of 2nd hand sets WON'T have the short right shift, though, so in truth, there are a lot less sets out there that fit the Pure.
5. The Pure has backlighting, but the switches are mounted "right way round" so the LED's are at the bottom of the switch. Some Poker 2's are backlit, some are not, but you can add LED's to the non-backlit ones to give them backlighting. More importantly, the switches are mounted "upside down" except for the space bar switch, so the LED's are in the correct place for proper backlit keycaps.
I love my Pure, but sometimes think I should have gone with a Poker 2 instead. Problem was that I couldn't find a Poker 2 ANSI locally, only ISO, but I could find a Pure limited edition with ANSI layout, so I got that. I really like the Fn layer and think it is THE best 60% Fn layer out there, but as I said, you can program the Poker 2 to have the same layout on the Pn layer.
The only 3 benefits of the Pure over the Poker 2 that matter, IMHO, are:
1. You can open the switches to mod them more easily due to being PCB rather than plate mount, but it's not much of an advantage since you have to desolder the LED's to do it and it's not THAT much more work to also desolder the switches you want to open.
2. It has both the Esc AND ~` key on the default layer, which is really nice if you work in Linux.
3. You can toggle the right hand modifier keys into an upside down T arrow cluster.
Poker 2 over Pure:
1. Plate mounted feels better IMO.
2. More keycap options.
3. More case options.
4. LED's are better positioned for "normal" backlit keycaps.
5. Programmable.
6. Easier to find nowadays, too.