I will admit, I am a softie and I adore romance in RPs. That being said I don't ever participate in RPs where romance is the point of the RP. I can't see myself having fun with that, ever. I need meat, not sugar. But as so many here have said I find it to be a great way to add depth to a RP when done right. I adore it as a GM even if it isn't with an NPC because it gives me more tools to work with, people to kill off, weapons to work with etc.

Done right can be hard, because pacing and timing can be tricky, especially in a group and things IC move much slower. So that people who are enthused by the Romance might forget that while the RP is over a month old, the characters are only newly acquitted and professing their undying love after 20 mins of interaction is a tad much. 

It is certainly easier and more natural to pace in 1x1's but it can be done in groups even though it is much trickier as I said before. I've had a few group RPs where the side romance of some of the PC's and their focus on it took them out of some plot important happenings and side lined them for over a month while the group "caught up.". Their 5 min make out-session kept them out of a plot important scene that took about a month of OOC time to finish and they were left cooling their heels. 

I'll also add to further hammer home a point made above, Romance =/= sex. 

Seduction and romance go hand in hand and can be RPed out (because seduction isn't just sex either) but there are certainly classy ways to handle it IC even in a group that do not make the others feel uncomfortable. Because I've been in a few of those, group RPs where we had to tell people, "geeze, get a room!" and they didn't. :/

So that's my early morning, pre-coffee take on romance in RPs.