Well at least your comparing apples to apples. As far as quality your questions is more like asking whats better the BMW or the Mercedes. The truth is you could not go wrong with either one. You probably did not get as many replies from MP9 owners because there are not as many. Due to it just being released in Sept and an $850 price tag. The 808 will have been on the market a full year soon and is $200 cheaper.
Anyone telling you any modern buggy out performs the other is full of it. All modern race bread buggy's performance is on a pretty equal level. The industry has now become so competitive that there is a minimum standard there vehicles must perform to in order to compete. Keep in mind on any given Saturday at any give track any buggy can beat any other buggy. And it happens all the time its really a matter of whose got the right setup and the right driver that day.
If your driving a Losi now neither of the buggy's will be any more bulletproof than the one you have. They may wear better but will survive or not survive a crash in about the same manor. Bulletproof = maintenance + luck + driving skills that has not changed since the dawn of RC'ing. As far as performance keep in mind they were all scrambling to redesign there buggy's to compete with the Losi. (no disrespect to either buggy) Losi stepped the level of what a buggy's performance should be which is a good thing for everyone.
As far as which one you should get that should be simply a matter of which one you liked the best. They are so equal in performance and quality that there is not a wrong choice just a delayed choice. Waiting for someone to give you some magical answer that simply does not exist. Pick the one you like for whatever reason you liked and you will be very happy.