This was a regular topic for a long time. It seems that everyone bought something which suits, and isn't in the market any more.I got the top of the line Canon, an 8800F. It has been good, but may just have failed.
At the time, it was rated second behind Epson V550.
Currently, it seems that Cannon 9000 has replaced the 8800; Epson V550 exists, also V600 (and I am not discerning the difference).
The Canon would hold A4, but it had to be placed in the centre of platen by judgment. It could be placed along an edge, as scanning didn't go to the edge of the platen.
Any comments or recommendations from other users?