I was running an ICS ROM on my Fascinate before picking up a Charge on eBay (I wanted 4G and bigger screen). ICS can run on these older devices, and the ROM was as smooth and quick as any GB ROM I've used. But I would not say it was earth-shattering to have ICS...the differences, to me, were barely noticable. But that could also have more to do with the fact it was running on a much older, single core device. I'm running Tweaked 2.0 on my Charge as well, and this phone is still far superior than my Fascinate with ICS running. How much better could the Charge be with ICS? Maybe a little better, but again, probably nothing that would make you say "Holy Canoli, this is amazing!".
I think it's funny how people get so caught up in the idea that they "need" ICS. And don't get me wrong, it is nice and I was chomping at the bit to get it on my device as well. But if your phone works, and works well, without the latest and greatest, just enjoy what you have and relax a little more!