I'm baffled by this sort of response - the new models are 8 months away, and people are already throwing their toys out of the pram over this. You can still play with what you've got, you can still order models that you haven't got yet (I know I will be!) and take advantage of the unpaintedness of what's already out if that's what bothers you.
I've only just started SST and I still have to complete my Exo platoon, my CAP troopers, and my Bugs. I haven't even thought about Marauders yet, but I imagine I'll get some of them too.
I will avoid models that have been mentioned as being significantly redone (i.e. hoppers) but I don't see any point in not buying the existing Exos, ripplers etc. - as I say, why are people complaining that this is the end of SST? The game is playable right now, has great models which are staying in production (and look identical to those we've seen in the new style). As for the rulesbook update, you've been asking for it for ages, and I think Msprange already mentioned that the new version may be given out free in S&P, so it's not as if you will have to buy them again.
All I can see changing is possibly the army lists, though I really hope that this doesn't become 'boxset-centric' and eliminate the customisable squads/armies we have atm in favour of building things on the boxed sets.