The Series 3 will no longer receive OS updates starting this fall (outside of security fixes). In other words, do not purchase if you want something that will continue to receive the latest in OS updates.
I put this FIRMLY on the** DO NOT BUY** list. This watch is now End of Life.
(Look at the release dates vs the End of Life Dates)
This model watch launched in 2017, 4 years ago.
Buy any other newer watch (including the SE).
The 90 day warranty does not give me the warm fuzzies about buying this refurbished from woot, however, that’s a part of the reason that the watch is cheaper than buying from Apple; after 90 days you’re on your own for any issues you might have (honestly - with the stories I’ve read in multiple different comment sections when these watches come up for sale I’d just buy direct from Apple - it might be more money but you’ll get a 1 year warranty on the device).