The only thing that is awesome about it is a handful of features more so in the newer version on the GS 3

(but the majority of these have now been ported over

)
Originally it was amazing when the GS 2 was top dog, largely due to how smooth and quick it was compared to sense etc. and having superb media playback (still does, but sense V4 is much better in this area now, touchwiz would still be better though and the SE's skin/software is also very good at this area) but now nearly all the top-mid end phones are extremely quick and smooth and the difference will be even less once phones get JB and for the other areas they are more or less the same as well, strengths and weaknesses here and there etc.
Essentially it just comes down to what you like the look of the most regarding the UI, stock apps etc.
Touchwiz just needs a complete over haul for the stock touchwiz apps and colour scheme/UI.
But yeah just like the majority of android phones, there is no reason the GS 2 shouldn't get JB, but then again there was no reason why the desire couldn't get 2.3 officially (and yes I know that HTC did "try" to bring it and have got an update available to dl online, but there was no reason why they couldn't have dropped some sense stuff to make it work perfectly well and release it publicly/OTA) as well as many many other phones and the exact same goes for ICS and the nexus one, desire HD, galaxy S etc. etc.
It is just the nature of android and the biggest weakness, which unfortunately google don't seem to give a **** about
The phone is more than capable of receiving the next version of android whatever it will be 5.0, however, the chances of it getting that update are pretty much zero where as the GN will probably get the update.