I'd take the Saudi's over the Glazers any day of the week.
Unlike the Glazers (who seem to focus entirely on our past to milk as much money as possible), the Saudi's would focus solely on the future of the club. As a fan, I am extremely proud of our history but I'm getting pretty fed up of being constantly reminded of our past achievements (the 1999 Treble or the Class of 92 for example), while our rivals seem to be planning for the future (e.g. stadium/training ground developments). We are making the same mistake as Liverpool in the early 90's, by focusing solely on our past.
A great history is fantastic, but being the best in the present is far more important for the future prosperity of the club. The next generation of football fans will not care less whether we have dominated in the past, long before they were born. All that matters is the present, and at the present they will choose the club with the best players, that play the best football and have the best stadiums. At the minute we are way behind in all these areas. Yes, Old Trafford is a fantastic stadium, but requires serious investment which I don't think will happen under the Glazers. Personally I don't see us ever being the best again under the Glazers, while under the Saudi's I do.
Manchester United deserves the best and the Saudi's would settle for nothing but the best. I imagine that they would invest massively in an Old Trafford stadium redevelopment, and we would go after, and more than likely get, the best players in the world. At the minute, we have the resources to compete with any club in the world, however if the next 6 years are like the last 6 years, we probably won't in the future. Eventually the money will start to dry up and we will start to fall behind. The Saudi's would safeguard our future.
Let's be honest, if the Saudi's do not buy us they will look to buy another club. Imagine if they bought Liverpool for example. We'll be competing against our two main rivals that have unlimited money while we'll be stuck with the Glazers sucking the next billion out of our club.