My general power tool philosophy is to buy the best tool you can possibly afford, then buy the next one up from that.
That being said, my first lathe was a $200 Excelsior mini-lathe from Rockler about 4 years ago. I had never turned anything in my life and wasn't sure that I was going to get deep into turning, so I didn't want to start out with a large investment. About a year ago, I added a NOVA DVR-XP to my shop -- what a honey of a machine, but definitely a budget-stretcher. I still use my mini for some things, almost daily, but I do almost all my turning on the NOVA.
So, yes, I am one who turns on a full size lathe.
I'm not personally familiar with either of the two lathes that you mentioned, so I can only give you my general thoughts on them. The Rikon is a midi lathe, but has variable speed which is really nice. The NOVA is a larger, full size lathe with a swivel head, but you have to move a belt to change speeds. However, I believe you can get a variable speed controller for it.
Both brands are good and if that's what your budget can afford, then either is probably a good choice. However, if you are really considering a full size lathe, especially if you think you might ever want to do other kinds of work, then I would suggest looking at a really nice machine like a NOVA DVR or another similar sized lathe.