One word answer: Glorious.
A Dumble ODS is a great sounding amp for most applications. To my ears here is how I would describe the Dumble ODS. The amps are not very bassy, but do have a good deal of low end especially through 12" speakers. The frequencies that are emphasized on the ODS are the highs, upper mids, and mids. Compared to a 100w Marshall the 100w ODS low end range cannot compare. The overdrive is a lot "looser" than a Marshall or Fender. Almost like an old Mesa Boogie Mark I, pretty compressed. The amps are basically set up like a Fender Twin or Showman (tons of headroom for cleans) but the overdrive section is it's own animal. With the midboost + PAB it quickly looses it's Fender roots and can be pretty rockin' with the right EQ. The more you pour on the gain the more Marshall/Mesa they sound.
Now there are the HRM and non-HRM models and they do sound quite different. The HRM models are a little more aggressive and articulate, less of that syrupy fusion sound. Don't be fooled though, the famous Dumble tones of Ford/Carlton can easily be had with a HRM. So in a nutshell the clean channel is a lot like a high powered Fender amp, the gain is like Fender/Marshall/Mesa mixture.
PS. take your time man and get what you want. Don't settle on something you won't be happy with, life is too short for that. Besides if you don't like it Ceriatones have great resale value especially because of the wait times for the OTS!
'67 and '74 Fender Twin Reverbs, '74 Marshall 1987 lead mkII, Metro Superlead 100. Pedals from TC Electronic, Ibanez, Dunlop, BK Butler, Electro-Harmonix, Fulltone, Maestro/Gibson, Loopmaster switching, VoodooLab, Boss. Gibson and Fender guitars, Dimarzio pickups.