I'm considering getting one because they offer substantial savings and then selling my 2012 once I get it back from Apple as it's one of the 128 GB SSD failures. Also, I have a Time Machine backup from the laptop that failed. Any reason I wouldn't be able to restore it to the new one if I did make the purchase?
refurbs
should come with Mavericks - if not, then it'll be a free upgrade.
the machine you'll receive will have had a fresh erase and install and thus will be nice and snappy.
as for TM backup, the answer to your question is a 'yes' - but why not consider a manual dropping into place that which you really need (by way of Documents, Movies, Music, Photos, etc - thus preserving space and of course you still have a compete backup available of all your old stuff and won't be inheriting any 'problems' that you may have had on your old machine
just a thought)
You can also then reinstall any additional Applications you may have had. Most can simply be dragged over into your new Applications folder and will run quite happily.