My GF and I met after we'd both been riding for a little while.
I'd ridden in the dirt as a youngster, so a lot of stuff comes naturally to me, while she only started in her twenties, so things are a lot more cerebral, and it annoys her when she asks how I handle a situation or why I do something, and my answer consists of, "I just do."
We both were on 250s when we met, then I went to a YZF600 Thundercat and she a 2004 ZX6RR. After we took a break, I now have an FZ6N and she a Triumph Street Triple. She usually has the 'faster' bike, while I tend to be the 'faster' rider. That facet has never caused us any issues as a couple or me as an individual. She admits that the ZX6RR wasn't right for her, it was too tall.
In my opinion, pros far outweigh the cons. I don't like riding solo for fun, and partly a little for safety. Come a weekend, I have a riding partner usually more keen than I am, ready to ride, although she is a later riser. This is fantastic.
Any issues we have are totally unrelated to the bikes. She does want me to get louder pipes for 'safety' though.
EDIT: We did get intercoms, and it's pretty good actually. We've had one argument over the intercom. I was ready to head straight home to be on time for my friends coming over, while she wanted to hit more twisties. We compromised and I got home just in time.
Pic: See, it did happen. FYI, she'd taken her jacket off. We ain't no squids.
http://a2.sphotos.ak.fbcdn.net/hphotos-ak-ash4/336566_247428368667231_1334760443_o.jpg