To my ears with AR there's a real dividing line over the past 10 years or so and everything that came before. I find the modern AR sound, in SS or Tube, much more enjoyable, fun and natural. Of course, saying that immediately puts my life at risk from those early AR die hards. The point is, you should learn which AR sound you like first.
Before buying I'd also listen to PrimaLuna, Conrad Johns on and Cary.