It sure does sound dramatic. Not that I ever tried riding with a +1 chain, but the only difference is a few 1/10 mm in width. The difference is so slight that many chain sets are in fact both 10/11 speed. If anything at all, I would expect increased noise from the chain rubbing on the cogs and possibly some false/ghost shifting from the (too wide) chain catching on the shift ramps. All the other issues sound more like issues with the adjustments rather than the chain.