what car do you have. we found the tobi did not fit in our car AT ALL. so make sure you check it out. the straps on the priori xp kept on twisting and drove us mad. Apparently there is a way to fix that though.
I have had both and prefer the tobi (if it its your car). You dont have to loosen the straps the same way - once you have unclicked them you just pull them out of the way, and get child out - well easy! It is also a lot easier to fit as the car seatbelt goes round a different route/
Not sure the price difference is worth it thoug, as you can get the Priori at discounted prices on the net!
We have 2 Tobi's. They are easy to fit and VERY secure once in- they do not move at all. they don't seem to recline as much as the priori when fitted but are dc's don't seem to find this a problem. I also like how you don't have to take them out of the car to adjust the height of the shoulder straps.
My dn has a priori and the straps keep twisting and getting stuck.