-How's the battery life? Both in the Developer Preview or not. Because in my 820 is really sucks, it needs three times charging a day and I even had used the MPJ's 2500 mAh battery. (I'm on the Lumia Black Developer Preview 8.1)
battery life is decent, its not amazing, but it lasts through an average day for me with about 30% left
-Is it too late already to buy a 925?
Well, that depends, the phone is officially EOL (atleast on T-mobile, but probably the same case on all carriers) so cyan is likely its last official update, though you always have the dev preview to fallback on. It's a nice phone, it feels nice to hold, I get a ton of compliments on it out in public, it has one of the most beautiful displays (gotta love OLED) and it just all around id a great phone, and with the EOL, its price is pretty low
-How troublesome are the 16gb capacity? Mind it that I'd only store about half five hundred songs (300mb) and I don't play games in my phone, and the rest are used by the social and media apps and the photo editor apps and the photos and videos I take on it.
I think you'd be fine, I struggle with it, but I have tons of music at 320 kb/s bitrate, for just social media? pfft, that wont take anything space wise
-And how would you rate your 925's camera? Both front and back.
I haven't used the front camera much to give a good review on, from the times I did use it, it seemed average.The rear camera is great, it doesn't take OMGAWESOME pictures, but it wows friends and family, its really good in low light conditions too.
conclusion: If you don't mind getting an aging phone that likely wont keep support long (if it still has it) then yea, I'd definately recommend this phone, it really is a nice little thing, and, this is just my personal opinion, but I think it has the best body design in all of the lumia series