One Incher - based on your recent distaste towards black metal (whether it be satan worshipping or not), I wouldn't rush out to get this stuff...
...with that said, I've never heard Watain because I like my penchant for big hairy gorillas, so I can only speculate. (And before anyone says STFW, where can one find some Watain for jew-cheap)?
You're instincts are right about Weakling though - they are a variation of BM, with some punk influences shining through (a la Darkthone), but they seem to capture quite an ambient, evocative atmosphere. Note that the guys behind Weakling (RIP) are the same guys from The Fucking Champs!!!!
Have you heard any samples of The Fucking Champs yet? Hahaha, just a bunch of guys playing the best fucking metal riffs you can think of. No vocals, just riff city. Just go to Aqaurius Records for samples on all the above.
P.S. BEFORE THESE TWO BANDS, FOR THE LOVE OF GOAT, LISTEN TO YOUR MEADS OF ASPHODEL CD-R. IT HAS YOUR NAME WRITTEN ALL OVER IT IN GOAT SPERM!!! (Honestly man, it'll give you wood, and when I say 'wood', I'm talking about the kind that you might throw into your fireplace!!!).