Been with HSAbank pretty much since they started (I had an "MSA" originally, which was the precursor to the current HSA). the only problem I ever had was when I could not withdraw money easily to pay for expenses related to a medical emergency we had while traveling. It took like 12 months to get everything taken care of (total bills were about 300,000, the insurance took care of about 250000 of that, I paid 25000 from a savings account, and the HSA funds paid the rest). Anyway, things are coded as either "medical" or "not medical", so they automatically were rejecting the expenses that were a little ambiguous, like the Flight for Life airplane we needed or the extra long ambulance ride (who knew that, after 25 miles, the costs balloon? A 50 mile ride cost us more than 5000). The airplane ride was not coded as "medical"; even though it was like a flying ambulance, it was coded as a travel expense. You are not given many choices during an emergency, and you are not necessarily making decisions with an eye on the money if there is a life/death event occurring. And, as in the case of our long ambulance ride, you may not get to make the choices at all.
Anyway, read the fine print and be sure you review it every once in a while. I wished I had done so when I was in the midst of spending money I was going to request reimbursement for. The HSA was the best decision I ever made and the high deductible policy worked perfectly when I needed it to. I'd have a lot more money now if the incident had not happened, but I have saved a lot of money over the long haul.
(Everyone was fine in the end, by the way... just a little hemorrhagic stroke, brain surgery, rehab, physical therapy and what seemed like a million CAT scans and MRIs)