I think that differentiated classes within a grade works better than having a teacher CONSISTENTLY have to find time to differentiate within a class. Admittedly, however, you need a big school or many teachers to pull this off. The problems that I've observed with simply asking a teacher to differentiate within a classroom for your child are: VERY hard on teacher, even if very well-intentioned, to point where it almost doesn't happen (or starts OK, but falls apart); teacher never really understands just HOW ADVANCED the child really is - they go in with an "enrichment packet" they think is suitable for a slightly advanced child and never really realize what level the child is actually at; or child ends up working alone which is tough at a young age (and can even be when older) and child starts to feel disengaged or isolated.
We've experienced all of these issues, unfortunately, over the years. DYS DS7, is currently isolated, but with a better plan for next year and with a great teacher who finally gets him and is working for future acceleration. We've tried enrichment for a couple of years now, and even with really great, well-intentioned teachers, it has just fallen short. Unless they can come up with a class for him, acceleration appears to be his best option right now.
But every situation is different, of course...
