Coilpacks came about due to cost, ie it is cheaper to make than a dizzy, plus more reliable.
Dizzies can wear badly the crushed iron particle bush on the std ones, does not cope well with any amount of getting too hot, I always replace these with oilite.
A std ignition system in decent order will cope perfectly, but of course any extra bit these have compared with coilpacks is just one extra potential bit to go wrong.
I had a stutter on my old L6 ecu, despite being pronounced fit for service, but it was only slight, just above idle when reapplying throttle, so could work around it.
Found out what it was when new ecu went on, as it was horrendous, and had to fit a new TPS(universal one) before mapping could be easily accomplished, as it was stuttering massively when new ecu wasn't pouring fuel in like old one, whcih masked the problem mostly.
I had done a voltage check moving tps as slow as possible but could not find any dead spot on old ecu.
tabetha