Aviall is pretty good, if you're not in a huge hurry or mind spending $$ on AOG shipments from the Dallas warehouse. The local sales outlets don't seem to have enough stock on the shelves.
Check on prices too. Aviall seems high on some items like hardware (nuts, bolts, cotter pins, etc.)
I don't like buying tires from them, unless they're running a deal on them. Batteries seem OK though. If you're buying batteries, buy a bunch of electrolyte at one time since the haz mat charge on shipping is high. The haz mat for two quarts is the same as 15 gallons, so I would get a bunch at one time, enough to service 8-10 batteries, and only get batteries as needed.
I never had a problem with shelf life limited items (ELT batteries, etc) because they move large quantities over the shelves.
For Lycoming engine items, I mostly use Superior Air Parts, unless the customer has a preference.
Personally, I don't like having only one or two suppliers.