I just wanted to throw in my .10...
Go out and listen to both, buy the one that sounds better. There are lots of get-togethers around the country, some DIY, some commercial. Go out and hear some well designed ribbon speakers or ones with ribbon tweets (from Selia, Salk, VMPS, GR Research, etc.) and listen to some well designed speakers with dome tweeters (Ellis 1801's, BESL, GR Research, etc.).
This thread shows how different people prefer different tweeters. I like things about both but can only afford one system so I go with domes. The OW1 tweeter is one of my favorites. It may not blow you away in a 30 second demonstration like some tweeters but it just sounds so natural and sweet. It's the kind of thing you appreciate over time. Then again, I also like the Arum Cantus ribbon tweets. Longer tweeters will have limited vertical dispersion but that can be a plus because of less room reflections...unless you listen to music while standing up and walking around. Also, I've never blown a tweeter, ribbon or dome. I'm very careful and don't have any children to mess with my system. That might have something to do with it.
There is no shortcut, you have to go out and listen to everything you can. Bring your own music and get familiar with some well recorded tracks and play them on different speakers. Just remember, good speakers on bad electronics (or poorly matched) will usually give you bad sound. Make sure when you are evaluating speakers you are actually evaluating speakers not a poorly matched system.
In the end, you will be the one who has to be happy with your system. Don't get swayed by flavors of the week. Just listen to everything and get what sounds best to you. Also, don't worry about making the "perfect" decision as you will most likely make changes in preference. This is more like dating than marriage.
Good luck,
J