The RY4 from KalamazooVaporShop is really good, as is the Sweet Caroline from Ivape.
The RY4 from KVS has that classic caramel
tobacco taste with a hint of vanilla. Highly regarded from what I've seen in the
reviews I've read. I like it a lot.
The Sweet Caroline has around the same flavor but slightly nuttier, IMO. Although this one is a little different from the "classic" RY4, I just can't place what it is.
IVape also has a menthol version called Carolina Crush, which I am quite fond of. If you like menthol, of course. Both are quite good at lower voltages but really shine once you get between 4.5-5.0 volts.
www.kalamazoovaporshop.com
www.ivape.com
I am in no way affiliated with either of these shops. These are just my opinions. I've had good experiences with both.