My local Performance is currently my main LBS. I'd give them about a B- overall if I were to grade them. I think they offer good value; especially for someone relatively new to cycling like myself (< 2 years). I like my Scattante X-330 CX bike (very responsive and stable bike/frame for the price) but I had them clean everything recently and the shifting seems off. They did a very good job bringing my '88 Fuji up to snuff. Like some of the posts above allude to, it totally ticks me off that they sell items in their store more expensive than the same thing online. If you call them on it they'll give it to you for the lower price but that is bush league. I think their clothing is a good deal. I also have the Forte tires on my Fuji (strada K's) and have not had a flat in over 1600 miles.
Overall a mixed bag with very competitive pricing. They certainly are not a polished first class outfit, however.