Well, my opinions on both:
Yamaha THR10:
Pros: Cute. Small. Lightweight. Stereo speakers. Some good crunchy/gainy tones.
Cons: Pricey for what it is. Cleans (to my ears) get really flabby when the volume is up. Pretty much limited to low-volume practive and recording - kinda hard to jam with unless you output it to a PA or something.
Mustang (and I'll use the III for example; $20 more than the THR10, and I have owned a MIII for awhile):
Pros: Versatile. GREAT tones, especially the cleaner Fender models. Good tones whether whisper quiet or deafeningly LOUD. Don't need the software for the "deep" editing, although it makes it easier. Celestion 12" speaker. Can be used from home practice and recording to standalone rehearsals and gigs (took mine to Pragestock, and never had the master above 4
.).
The cheaper Mustang I and IIs are OK, and may be enough for your purposes, but if the THR10 is in your sights, you can get the MUCH better MIII for the same money, plus it's usable for more than the home.
All in all, I would go with either of the Mustangs over the THR.