I would say that with the larger rim, you will have a smaller sidewall on the tire which will give you more of a harsh ride.
Some people prefer a more harsh "sportier" ride, so the 14s may be just up your alley. Either way, the Bighorns ride great, so harsh ride even with 14s probably is a non-issue.
If it were any other tire than the Bighorn, I personally would choose the 12" rims.
There was a guy running Bighorns on a Rhino 660 with 14" rims on this site, or maybe it was the www.atvnation.com site, and he had nice pics and a nice writeup. Do a search on both sites. I know it's out there. That may help you to decide what's right for you.
Some people prefer a more harsh "sportier" ride, so the 14s may be just up your alley. Either way, the Bighorns ride great, so harsh ride even with 14s probably is a non-issue.
If it were any other tire than the Bighorn, I personally would choose the 12" rims.
There was a guy running Bighorns on a Rhino 660 with 14" rims on this site, or maybe it was the www.atvnation.com site, and he had nice pics and a nice writeup. Do a search on both sites. I know it's out there. That may help you to decide what's right for you.