none.
Even if the GE Filter Flo and the Kenmore 80s series have their flaws on what comes to washing results compared to Euro machines, even IF the sink-top portables (the French "Calor", the British "Burco" and the German "Cordes") impeller machines have a lousy washload/water consumption balance, even IF I would only trust my loved Lavamat FL once it comes to really CLEAN clothes: I have tried them all and I would never want to miss any of them. They all have their own spectacular mechanisms and wash actions (and sounds, I could kiss them all for that ;-)
Talking about service calls? NONE of them, they all keep going strong. Some for 1 and some for 4 decades. Nothing whatsoever. Maybe a seal here and there, but that was it.
The only thing I once was thinking was: "what the F...... do they think? (they = the engineers) Just assuming 1-2 mins of wannabe rinsing theatre would do?" (I myself would have expected the inventors to wait at least for one or two full rollover cycles before rinsing is done). This refers to almost any classic toploading American washer. The first time I saw this in the US (before I owned any washer at all) was in the 80s, I thought: Goodness, down there some t-shirts are rinsed, but up here most of the clothes are only wiggled around a little in vain, floating about a bit for a good impression only and now suddenly everything is over and these gallons of clear water are pumped out (it got even worse when I saw the minitub GE: socks only rocking cozily in some foam with no washing action at all).... what a hooey! Do buyers believe that? My gosh.... these GE guys have stopped thinking halfways (this is what I thought that day, correct). While the GE FF is probably the best in soil and sand removal, the timer is a joke (long pauses, shortest useless rinse cycle ever)
A friend was over at my place, watching the GE: He said (in one of those looooong timer breaks): "hey, what's wrong? I got another song going in this jukebox! Want my money back!" He hit bull's eye, this was unspoken yet but very true.
Nevertheless: I do LOVE all my machines. None of them have failed me ever.