20+ year old 6A on my big block never gave me an issue. Ended up converting to EFI and am using that to control the timing, so I don't use the 6A anymore.
I have run M S D 6`s on four diff. hot rods , 67 hemi belvedere , 72 406 vega , 92 406 gmc pick up , and now a 505'' 68 fastback , and never had one fail !!
None digital tho...the one on the fastback has been on there for 12ish yrs ...
