i use ribbons in the studio all the time and love them for their warm smooth sound on classical material. i have used blumlein pairs of ribbons for live venue recordings on occasion, but i dont think i would want to use them in any kind of large rock venue, or from any kind of distance. ribbons are also very low output mics compared to condensers, and require good preamps with lots of clean gain. most ribbons these days are not nearly as fragile as those of past years. i've owned pairs of coles 4038s, royer r-121s, and these days, i am using the very nice (and affordable) shinybox 46mx's (love em).
if you are doing classical or small acoustic ensembles, ribbons can be great if you can get close (ie, on the stage), but if you are doing rock from distant locations in the audience, stick with sd condensers with hypers for best noise rejection.