rookie questions about used Bryston BDPs

I'm new to digital audio (and new out here), so be gentle with my ignorance!

I'd like to take the digital dive. I'm interested in streaming (Tidal and perhaps eventually Idagio or Primephonic); maybe Roon; definitely a hard drive with a range of music files, none of them obscure, many MP3s. That's it for now. Much of what I have is in iTunes.

For a few reasons, I'd like to go with Bryston. I can't afford a new BDP3; the Pi is doable, though as an experiment it's still pushing my budget. It doesn't look hard to find a *used* BDP1, BDP2, and BDP Pi. Almost certainly the BDP1 and BDP2 would be out of warranty; the BDP Pi would still be covered. My questions: assuming the used equipment is in excellent condition, would you rather have a BDP1 (at a modest price), a BDP2 (with or without the upgrade), or a (newer, under warranty) Pi? To tweak the question, if the BDP2 (let's say without the upgrade and out of warranty) and Pi (under warranty) were close to the same price, which would you choose? Full confession: I don't really know what the upgrade does, even after reading about it.

I understand that the BDP2 will have some features that the Pi doesn't have. I'm not sure if I would need those features; my needs seem pretty basic for now. Maybe a used BDP1 would do what I need. The subtext for my questions are obviously: is the Pi more "current" than the 1 or 2? Would the 1 do everything I need for now? And how important would you say the warranty is? 

Thank you for reading!