Peter, those are both good options, of course, but the Kremona is there for folks who want to easily amplify their classical guitars without alteration. And the Kremona works even better when paired with a multi-effects box with a volume pedal; EQ is available for controlling feedback, volume control too. As a flamenco player and someone who likes to use the guitar as a rhythm box as well, the fact that the Kremona picks up sounds from hitting the guitar is a plus, and the cable can easily be secured with a little velcro so that it doesn't interfere. But, for higher-volume ensemble work, your recommendations are reasonable; I have a few guitars with the RMC system built in, excellent sounds, but really pricey. I find that the Kremona on one of my luthier-built guitars is great for background music gigs, wedding ceremonies, small string ensemble concerts, and even concerti; I recently worked with a chorus playing Castelnuovo Tedesco's Romancero Gitano and Jeffery Van's civil war poem setting for guitar and chorus, Kremona worked very well.
Lester Devoe Flamenco Negra
Lester Devoe Flamenco Blanca
Aparicio Flamenco Blanca with RMC pickup
Bartolex 7-string with RMC pickup
Giannini 7-string with Shadow pickup
Sal Pace 7-string archtop