diplogramma will grow to a similar size to micro ,maybe a bit smaller , and just as capable of ripping anything up.
it would depend on what tank you are thinking of , pleuros are probably the main channa that people seam to get away with in a comm tank if you just wanted one ,but they still need quite a bit of room as they swim none stop ,a tank of at least 7foot should be considered. there are loads of diferant species out there and many that look far better than micros , if you want two in a tank ,then have a look through one of the stickys and see what species you prefer the look of and can house correctly , then buy a small group of juvies and grow them out until a pair forms , then you will have a very impressive pair swimming around , there is a snakehead out there to suit most sized tanks , its just finding what you like most , if you like the argus there are some good argus look alikes ,i.e. maculata panaw ect , maculatas teeth are more impresive than a micros . but you may not like the pattern on them . pleuros are fantastic if you have the space , also maurloids is another but again like lots of room , if you tell us which size tank you are going for , we could supply you a list of all that are suitable.
cheers col