Post your line stats (SNR, Attenuation). Can give you a better idea then.
If your line is such that it sometimes resyncs at 1Mbit then either you are quite far from the exchange and therefore won't benefit from ADSL2+ or that there is interference on your line causing your snr to be lower than it could be. Try plugging your router/modem into the test socket and see how or whether your connection improves.
One benefit with ADSL2+ in the future will be the implementation of SRA (Seamless Rate Adaptation) which will prevent you from disconnecting. It will allow your sync speed to change (depending on your snr) on the fly without dropping the connection
As you may have read on ADSLguide, the Belkin 7633 performs admirably on Bulldog connections. It also supports SRA with the current firmware. I have one myself and my sync speeds have improved and i get less dropped connections but it will be pot luck whether you see major improvements in this regard with your line quality. I know a general consensus on these forums is that Belkin is a poor brand when it comes to routers but i have no issues at all apart from the wireless speed only being at 54Mbps. Their customer support is atrocious but hopefully, as it is for myself, it will be just a case of plug and play without any issues.
Anyhow, post your stats and we'll be able to give you more of an estimate of how and whether you will benefit from ADSL2+.
HTH

m