I've had good experiences buying batteries (SMC) and motors through br00d, and motors and PRS gears through EA. A lot of the "boutique" companies are providing a similar service with a different label. I'd pick one that not only has a good track record with performance and customer service, but is also active in the R/C community. There's more than a few matchers that seem to do nothing more than exploit R/C for financial gain without giving much back. Find a company that is nice to you online, answers questions, and is generally involved with improving R/C. Those are the guys that deserve your business the most.