I can't really speak to blenders specifically, but I do have a Kenwood food processor with a blender...attachment, I guess...and it works really, really well. It's
this one.
I've always had trouble with blenders in the past not being powerful enough to really crush ice when I make smoothies, aside from industrial blenders at the coffee shop I worked at. I haven't had the same problem with this.
Granted, it's not cheap (though we got mine on sale for about £75) and it wouldn't really be worth it if you don't think you'd use it for anything else, but it is ever so much more than a blender and I love it.
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It comes with lots of other fun gadgets. I haven't had a chance to use the juicer attachment yet!