Around South Florida you do see a mix of both RT series and F3 series.
In simple terms, the RT is kind of Can Ams Gold Wing Tour. Not truly a sport machine, but rather more touring fucused. The Spyder RT is not a racer, but certainly is no slacker either.
The F3T or Limited is more the more sporty touring bike, in some ways similar to the RT series, and compares to a Honda Gold Wing F6B. Again, not a racer, but a machine that is more focused for the rider and less for a passenger. Some people prefer that arms forward, feet forward position compared to the RT series more upright less stretched out position.
In terms of how the bikes are equipped with features, in general, they are very similar. The looks and seating position are the big differences.
Myself, I never came to terms with the looks of the F3 front bodywork. Also, we often ride two up, and for the passenger, our RT with arm rests is very confidence inspiring and relaxing to ride.
Everyone is different, for me, if I rode solo all the time, I would be on two wheels, simply what I prefer. We own the Spyder more for my wife, than me, using the RT series better passenger comfort as the number one priority.
The F3 was not available when we purchased our 14 RTS. However the ST series was, and with similar passenger seating as an F3, that falling off the back feeling was a deal breaker except for an RT.
Again, everyone is different.
Not sure which dealer you purchased from and shopping for an F3 at. I would suggest maybe seeing if someone local would let you do a parking lot test ride of their personal bike, just to get an idea. Also, call around, possibly another larger Spyder dealer like CFPS has a demo F3 you could ride or maybe visit them and have a loaner F3 while they do some maintenance on your RT. That would certainly help you decide.