Bass-Bone and Tuba are my equal partners. My own is a Yeo 822G. It's freaking awesome, and I take the second valve off often (I have a separate case for the assembly). It's a great instrument for a wide variety of scenarios, and it has an amazing dynamic capacity while also able to tongue on a dime.
For those who poo-poo single valves, besides needing to research the awesome career of George Roberts, Doug Yeo wrote an amazing article "In defense of the Single-Valve Bass Trombone" which explains partially why I play dependent and single valves exclusively... he's more eloquent than I.
All that said...
A Reynolds is a jewel... my Bb/F with a slide to Eb had an apocalyptic low end and was a sweetheart to play; I wish to hell I'd never sold it for a 184 Miraphone... except I loved that too... Things that play like it are precisely zilch. BUT, the Yamaha 612Rs are kinda-sorta close-ish. The 321Rs too... sorta. Phil Teale peals pain with his vintage dependent Yammys!
Olds Roberts singles are tasty fishies! The double valves are... not so much. Avoid the Roberts Yammy... great for recording mostly, not a hall.
The Dillon/Baltimore Brass Yama-clones are better than they have any right to be. See discussions about the Miraclone 186s to see what I mean. Very, very good player for the cash. The 820 Yamahas they copied are excellent as well.
I'd take a Getzen 1062FD any day of the week, but the 1052 might feel a little more stable for the average player.
Never discount a 7B or 8B. Try before you buy, but some are exquisite.
Thayer-valve bass trombones feel open because they leak - same with CL valves (ducks!). Honestly, I hate them physically on my neck and how they perform. Blech! To each their own, though. I'll play standard rotors until I'm buried.
My recommendation would be to patiently wait for a 622 Bass, the earlier Yeo model. Extremely good instrument, flexible, and damn near the same as the current Xeno. If you insist on spending real money, Look for a nicely seasoned Bach, or Shires/Edwards/Rath customophones.