I don't think it's very common, certainly not to the extent that the 41TE experienced, but there have been a few failures here and there. It's basically a 41TE with an underdrive compounder attached, and that compounder seems to be what goes out the most frequently with early ones the most affected. The 4 speed part of it seems at least as reliable as the newer 41TE to me, and they were pretty decent transmissions after 2001 or so.
Dad's 2008 Caravan had a pretty catastrophic failure at 140k kms that I figure came down to either the compounder or differential, but once it got a replacement 2010 model transmission from a boneyard it was fine. That van has 410k kms now and is still going. I actually really like this transmission... wish my 2004 Pacifica had it.