Actually the mame32 vs mame choice.. it isn't much of a choice you should only use mame.
Here's the thing...some of the simplier fe's only call the -listxml flag from mame to get data or don't call mame at all. For those fe's you can use mame32. If the fe,app,ect uses ANY of mame's other list outputs or queries then you have to use regular mame. Now let it be known that some versions of mame32 support all the flags and some dont. Since you never know from version to version if they are all included, it's better to just avoid the whole mess. Why the mame32 guys sometimes don't support extra flags is beyond me, but regardless you should never, ever reccomend mame32 as it might cause unforseen issues later down the road.
j5 can work with mame32, if you manually send the driver and clone data, but it's much easier to use mame. Dk can use mame32 but some of the driver status info returned is crippled. Similar things happen with 3darcade and other fes that allow filtering. Mame32 is an option but it is usually easier to use mame so you can never say someone is wrong by reccomending mame over mame32 unless they ask something like "I want to play mame games but I don't want to deal with a fe."
And I want it to be known that I have nothing against cpviewer, it just doesn't do as much as j5. J5 is rock-solid stable, so I'm not sure what you mean by that. We run into bugs occasionally, but it usualy involves the user having a corrupted cfg file somewhere or them using an odd-ball "transition" build of mame (in the early .100's, when the list output flags were being changed).
Easier is subjective, personally I think it's easier to setup an app once, for one game and then have it automaticcally configure all other games, even if the mappings differ than to setup another app for each control change, even if the inital setup is quicker. But that is just me, others will disagree and I have no problem with that. I think based on what the poster asked he wanted j5 rather than cpviewer in terms of how he wanted to use it. Your opinion might differ, but I wouldn't call reccomending j5 wrong or even "half wrong" by any means.
I didn't come to argue, so I'll quit now, I just hate to see someone being picked apart for giving realitively good advice.
later
I wasn't going to argue the points that were opinions, I just don't understand why you jumped on poor unclet when, save the mala advice everything was pretty much spot on.