I would definitely recommend the VirtuaPin plunger kit over the Nanotech (a.k.a. Pinball Wizard) kit. In fact I just swapped out the Nanotech from my pre-built VirtuaPin cab with a new VirtuaPin v2 plunger kit (I actually had to wait a couple months for it, though - seems like they are selling out frequently).

The Nanotech sucks to configure for the accelerometer input - in fact there are long threads over at vpforums about just trying to get it configured the best way. Even if you do get it so its input is centered properly, it is still unreliable. The input constantly "jiggles" a little bit, with periodic big spikes every few minutes or so. For TPA and PBFX2 I had to map it to the digital keyboard "hard nudge" keys because it was too unstable to map it to analog input. And then even with a fairly substantial deadzone set up, it would still randomly trigger a nudge because of those spikes.

Now with the VirtuaPin plunger, it auto calibrates at start up and the input is rock solid. I can map it to the analog stick of an Xbox 360 controller (emulated with x360ce) and get decent analog nudging with no random input (I think I had to crank the anti-deadzone up to increase the strength of my nudges relative to what the game is expecting from a regular analog stick).

The input on the plunger also seems better. I think it uses the full range of numbers more or maybe sits at a lower position at rest or something. I mapped it to the right trigger in PBFX2 and it seemed to work fairly well the first time I tried it (haven't had time lately because I've been playing my first real pin which just came!). With the Nanotech, I could never get the plunger to work reliably with PBFX2 or TPA and eventually gave up and disabled it.

Hopefully in the future if these games finally do a full cabinet mode like they've been talking about for a long time, native joystick control support will be better so we don't have to rely on key-mapping programs and stuff. But nevertheless I don't find the Nanotech's nudge input to be very reliable. That's the reason VirtuaPin created their own in the first place because they used to just use the Nanotechs.

As for software, I'll point you to a previous post I made: https://pinside.com/pinball/forum/topic/should-i-buy-a-virtual-pin/page/4#post-1621717

This database of input lag for various displays is awesome: http://www.displaylag.com/display-database/ The guy that started it is a competitive Street Fighter player.

And yeah just buy all the PBFX2 tables. Even the ones that aren't my favorites are still worth playing (ok...maybe not V12 ) and they're so cheap compared to any real life pinball it's such a good deal.