I have had 3 JTS cars and do feel they have somehow earned an unfair reputation, presumably from the early ones having a number of faults.
My 156 had 7k on the clock, and my other 156/current GT are nearing 80k. Both have been as good as gold with only the 156 needing a coil pack (and other age related bits like exhaust e.t.c).
The JTS has torque, doesn't feel quite as hindered as other similar 2.0 4 pots from the competition and makes an OK sound (though not as nice as the TS).
For me I love torque and I like the JTS engine, better then the 2.2 in the Brera I had.
Current Italian Cars:-
2004 Alfa Romeo GT 2.0 JTS
Previous Italian Cars :-
2003 Maserati 4200 Cambiocorsa
2006 Alfa Brera 2.2 SV JTS
1999 Alfa Romeo 156 2.4 JTD
2005 Alfa Romeo 156 2.0 JTS Veloce
2004 Alfa Romeo GT 1.9 JTD
2001 Alfa Romeo GTV 3.0 V6 Lusso
2002 Alfa Romeo 156 2.0 JTS