I'm in Australia, so when I recently bought a new Euphonium I didn't have the chance to try an Adams (no dealers down here) but I did try a number of instruments. I ended up buying a Gold Lacquer Besson Prestige. Close seconds were the Besson Sovereign 967T and the Shires Q41. If I had to pick between the Sovereign and the Q41, I would probably have purchased the Q41 to be honest and then swapped in some mead springs. Whilst there are things on the Q41 that could be better, it's hard to ignore the amount of bang for buck. Note that I'm only playing with a Brass Band, no other ensemble types.
SE Shires Trombone (1G Bell, TB47 Slide, Tru-bore valve), Bach 5GS Mouthpiece
Besson Prestige 2052-8G, Alliance DC3 Mouthpiece
Yamaha YCR2330 Cornet