I've been with them for 10yrs and they have never wronged me. The only reason I'm considering switching is the moral reasons with SOPA.
When you have 30+ domains on a single registrar it is a little frustrating to go through each one individually and get the authorization code, unlock them, and request the transfer.
Also, for me, I have domains that I did 5-10yr registrations on, so the transfer and getting 1yr free isn't really that helpful.
Just fyi, you can generate a csv of your domains and authorization codes by doing:
Domain Management > Tools Tab > Exportable List > click Add New Export button > All your domains > and make sure to select "Authorization Code".
As for locking or unlocking, in Domain Management you should be able to just click the select all checkmark, and click the Lock button to set the lock level on all of them.
None of that should be an issue, even when transferring in, a bunch of registrars offer a bulk transfer option. The real pains start to set in if you have gTLDs which have special gotchas when transferring or changing contact information/ownership. I probably wouldn't even have been able to transfer my .it domains out of godaddy if not for the fact I have a dual citizenship which gave me some freedom with the regulations -- though it still took me hours of trial and error.
One slight irritation on GoDaddy -> Namecheap. One of these sites has a bug where it's either incorrectly generating ACs with embedded double quotes, like ABC"345"DE, or it's not storing them correctly. I did the bulk transfer yesterday, and this morning discovered that all such domains failed with a bad AC. I'm working with Namecheap support now to resolve it.
So it's still a constant-time operation, but the value of C is growing for me.
I haven't got any GoDaddy domains so I haven't done it personally, but I think people on the other top story about how to leave GoDaddy had all that solved.
You could use the tools to export all your domains, get the transfer codes, drop those into NameCheap (with the SOPASUCKS coupon) all at once, then go back to GoDaddy and confirm the transfers to avoid a long wait. And they even let you keep the time you had registered.
When you have 30+ domains on a single registrar it is a little frustrating to go through each one individually and get the authorization code, unlock them, and request the transfer.
Also, for me, I have domains that I did 5-10yr registrations on, so the transfer and getting 1yr free isn't really that helpful.