What motivates you? Money? Prestige? The work? The clients? The coffee machine?
This is what I would think about....which may say too much about me...
1. Money - same? Better? Worse? If better....how much better? If worse, is it really worth the sacrifice? Don't go on 'promises' of quick promotion - you can only evaluate an offer given it's tangible attributes, whilst taking into account future prospects...but that is the FUTURE not now.
2. Setting up - you will have to set your network up again at OW...and essentially lose the last 6 months you've had. If you have done a sh1t job then this point is moot...move on.
3. With a short spell somewhere (someone will back me up I'm sure!) for the cv you've got to stay longer at the next place. No one likes a hopper! This will be something you'll have to explain when you move from OW....and giving the prestige reason will unlikely wash, as you'll be giving that line to the next people!
Unrelated point - just because they interviewed you 6 times doesn't mean they are better...and equally true of getting a job 'easily'.
From your post it is clear you are concerned about prestige and rankings. Lots of people don't have a job...remember how lucky you are!!