I've used Planet Limo many times in the past. Drivers are generally good, cars usually clean, although wide variety of vehicles (Mercury SUV, Avalon, Camry, Town Car, etc.). They typically show up and txt that they're on site about 15 minutes before scheduled pickup, but don't charge wait time until scheduled time. They do have fairly high wait time charges. Biggest gripe (and this seems to be the case with many services) is that I can only get a receipt by calling in later. At least they are pretty prompt in emailing it over.
Carmel I've used a few times. Positive experiences with the rides themselves. Drivers are good, nice clean cars. Prices are competitive. Drivers generally do not contact you until the appointed time that they're on site, so I usually have to hustle to get down to street level so I don't get a wait charge. I would like the advance notice like Planet. My biggest gripe with Carmel is that the customer service is SO unresponsive. I have 2 receipts I need to get from them b/c I never received them from the drivers, although they appear to have sent them to the email address I confirmed. I've called, emailed, and completed the web form multiple times each to have the receipts emailed or faxed to me, and I get no response. It's been WEEKS. I can't even reach a live person, and I've called at least 6 times, always leaving a VM which I'm now convinced is just deleted when the machine fills up. So frustrating.
I'm trying Allstate next. Prices seem really good and website seems useful so far. We'll see...