i have not tried the current Sentia personally but the AW products i have used and seen have all been top notch, some of the best out there. I have also had the pleasure of using the Tecra M2 and i have to say that it is the best of the non-AW machines that you mentioned. I can honestly say that if i was going to pick a non-AW laptop it would likely be the tecra M2. Several members of my family have them and love them, especially with toshiba's extended warrenties that cover accidental damage.
Both the tecra and the Sentia are light and quite portable and i know how bad it can get when you are moving from class to class and they will both be more than adaquate for notes or some light gaming. Just a side note that the Tecra M2's to which i am refering are all loaded 2.0ghz dothan models so i can't speak for the lower cost (less loaded) ones, but the quality is still the same.
I know that the brief experience with the older model of sentia that i have had was absolutely awsome, it was light and very mobile and i loved how it turned heads wherever it was taken. AW has to be the best for its looks, totally awsome. I know that the quality was exceptional and i loved that machine for the time that i had with it.
Overall if you want not just substance (Tecra M2) but you want the awsome looks and styling to go along with it go for the AW. If all your interested in is function then go for the Tecra...
Thats just my $0.02 ($0.026 if your from canada)