I have a THR10C amp, the "bluesy" model. Great little amp that reminds one of an old kitchen radio from the 50s. That said, it's a great little amp w/some Fx, amp modeling and Yamaha hit a home run with this one. What Jimi said +1.
Haven't played an ID Core but have played the ID15TVP, which is a sister amp to the ID Core by Blackstar. OMG, what a marvelous amp. Has 6 amp models (2 clean, 2 crunch and 2 OD) then 6 amp tube emulations that are great. Hitting the TVP button is akin to hitting a boost. However, the ID Core doesn't have the tube emulations that the TVP does.
Both the THR and ID have USB compatability for recording direct to your computer.
So, if space is the major issue, then I would go with the THR as it's as compact as you can get, has great features, almost looks like a piece of metallic furniture (albeit small), has USB w/online mods available.
If space isn't the major issue, get the ID15TVP with 10" speaker, weighs only 24 lbs and is chock full of goodies. A definite threat to the Fender Mustang series.