Just to clarify, all of the PI brand headsets are fully compatible with ClearCom beltpacks, in addition to full PI systems being fully interchangeable with Clearcom systems. I tend to like the sound of ClearCom slightly better, but it's a difference only I'd ever notice, and because of the latching mic
button on the beltpacks, I actually prefer the PI beltpacks for use with a phone-style
handset.
At the shop, we actually have a bigger
stock of PI than ClearCom, and typically only
send ClearCom when it's specifically requested. PI boxes are generally built really sturdily, the only problem I typically see on them is noisy volume pots, but that's easy enough to fix with a good maintenance program. PI is also great about replacing/repairing broken equipment for a reasonable cost when it's not a warranty issue.
I'll generally happily work with either brand of gear, and PI is certainly a great option to look at if ClearCom is out of your budget.