I have a ton of mail to catch up on and a flight coming up. Does Sparrow (for Mac, not iOS) support an "offline" mode? If I read, respond to, label, and archive GMail messages on Sparrow while unconnected to the internet, will Sparrow correctly "sync up" to GMail once an internet connection is re-established?
I use Sparrow daily, but haven't ever needed to use it offline. From a few different websites (after Googling), it appears as though people do use it offline, but that it is still slightly buggy. I found a blog post that talks a bit about how it works great offline. There was also this question over on webapps that suggests using Sparrow or Mail.app (if not the offline Gmail feature).
It should sync up fine since it's just another IMAP email client, but as usual, be prepared for the slight possibility of some issues arising.