In terms of just buying it, yes. At the very least to see what they thought they had to change, and if it really is fully compatible to have all the changes together in one spot.
As for playing it, 5e is my favorite edition of D&D so far, but only my second favorite D&D-like game. What brings me to play my #2 instead of my #1 is that there are plenty of people to play it with. So if groups I'm with move to it, there is no question I will to.
As for the campaign I've been running for the past two years, that's another question. I had generally positive results moving a game from 3.0 to 3.5. Again, depends on if my players will be in Anniversary Edition games and want to consolidate on a single ruleset.