Hello and welcome to the forum! :)
Have you checked out the comparison table here?
An omission is that the WD TV Live supports DVD Menus (with the current beta firmware and the next official release).
Also, the Live (and Live Plus if you live in the US and want Netflix) are more recent and better supported than the Gen 2 (which hasn’t been updated since December last year).
From a support perspective, the Live may be a safer purchase even if it has a few features you don’t need.
A Live or Live Plus will play surround files no problem (it’ll downmix to stereo).
Might be worth also asking this question in the WD TV HD forum to get the opinion of those actually using the Gen 2. Check it out here: