Interesting. I stopped buying the 60 in 1 as 1942 and Gyruss had very bad sound, and Galaga was lagging terribly. I tried the 276 in 1 and those three games are all perfect. What is the problem with the 276 in 1 ?

I agree some of the games on the 60in1 are not the best, Time Pilot is also a bit scratchy sounding particularly the explosion sounds but all the games have the same sound level and the sounds are the same as the original boards (apart from the minor distortions).
On the 276in1 you cannot turn the sound up very loud as it distorts BADLY, this is really noticable on Galaga in particular, also the sound level varies from game to game so if you get the sound level ok on one game some of the others are too quiet. Pengo is one of the games where the sounds are completely different to the original board which is really noticeable as Pengo has a very distinctive sound.
Another issue with these boards is the connections are not 100% JAMMA, the ground connection on pins 27-28(both sides) must be disconnected or the board will do all sorts of wierd things.
This means that if you are putting it in an existing JAMMA cabinet you must remember to cut these wires from the harness and make sure they are not connected together after the wires are removed.
I have bought a few of these but in the end I have decided it's just not worth the hassle, as the 60in1 is pretty well proven.

I must say the only thing I do like about the 276in1 is the ability to quit the game without having to wait for the game to finish.