And in my opinion it only gets better from there. My favorite episodes from Season 1 are Countrycide (the one you see next), and Cyberwoman (ep 4), and then the last 2.
As for season 2 there is only like 1 episode I don’t enjoy all that much (as in I will watch it, but not my favorite).
I hadn’t seen Who when I watched the first 2 seasons of TW, so it can stand on it’s own, but many things make a bit more sense when you have seen the rest of Who.
It is my current obsession (it has filled the void left by BSG, but hasn’t replaced BSG).