There is a 250 shootout in the latest TransworldMX magazine and I think their comments about the RM 250 are right on:
"Test riders raved about the plush suspension action and the bike's uncanny ability to carve an inside line, no matter how tricky the corner. The Suzuki has a light feel both in the air and on the ground", "As often as riders raved about the RM 250's tight track prowess, they commented that at speed in the rough, things got a little sketchy".
Regarding the engine: "Power-wise, the RM 250 is plenty fast and drew good reviews from testers. Low-end power is good, mid-range is great, but top-end overrev is average. Riders who like to rev their bikes out in each gear will struggle a bit with the RM, as it works best when shifted just before the upper echelons of the RPM range".
I am coming from a '02 CR 250 and the transition was initially tricky in terms of handling but after a few rides I loved the RM. The engine is much forgiving and all the concentration I used to put on my CR's motor I now put on my riding (turns, jumps, positioning, etc) and this has helped me to significantly improve lap times.