I used to and it depends on the type of yoga you do as there are plenty of different types. Best to get into a light/beginners class to start as some of them are pretty full on. I'd done yoga before but ended up in a 90 minute Ashtanga session with a lot of yoga groupies, couldn't lift my arms for a week!
Some have hot Bikram yoga, some Hatha, some general, all sorts really.
If you want serious core building though, pilates is great.