Just how slow is an AMD driven Toshiba?

Looking around, questions like these have been asked time & again, so apologies for the repetition, but I'm stuck!

My old Toshiba is coming to the end of it's lifespan, I think I've crammed too much stuff on it over the years & is now infuriatingly slow so have decided to upgrade. When I bought it back in 2003ish I went mid-high price range at the time buying a Toshiba Satellite M45-S351 which was running an Intel Centrino setup which I had been told at the time was the best available.

I'm now looking at the Toshiba Satellite A350D-203 which is being advertised for around £450. I really like the specs in general (4GB RAM, 250GB Hard drive, 16" screen etc) , but is running an Turion X2 RM-72 / 2.1 GHz.
The Intel Centrino platform version of effectively the same computer, the Toshiba Satellite A350-12J is on the same site for £520. How much difference will I notice for the extra £70 if I'm using the computer for day to day paperwork, internet, streaming tv & watching dvd's?

Stupid question number 2, while I'm at it, Satellite vs Satellite Pro - you seem to get less for your money with a satellite pro, why is that?

Any helpful advice would be greatly appreciated