"All games that are larger than 25 MByte won't run 100% perfectly playable until the needed prefetch information is available!"
Which is almost every single game in the library, so what % are they playable? 30? 40? 90? It doesn't say. How are you going to play King of fighters 2000 that is 700mb when it constantly has to load into the dreamcast ram because it doesn't have 700mb of ram. All the moves for each characters and the like. I can't see how 90% of the MVS and AES games would be very playable, especially the good games like Fatal fury series, KOF series and Metal Slug series.
I'd still say your best bet is the Neo Geo CD format.