Link and length in concept are great. But in execution by various companies I find issues. Tamiya has been fairly good, ESCI and Italeri, less so, and Dragon about the same...
Indy links- very tedious and often frustrating, especially on some multi piece types such as US armor (Sherman thru Patton) or Kfz 251s... Again quality varies by maker- AFV Club Centurion were a breeze, HobbyBoss Cromwell/Centaur, fairly good, Dragons modern Soviet stuff acceptable. Their M24/M46 links are an exercise in pateince to the extreme.
Gluable soft single length. Easy to apply, but none seem to last. All that I havebuilt have started to snap within a year or so, some quicker, some longer. Not happy with those at all.
Old School (heat joined) soft single length. some are horrid... too stiff, detail onone sideonly, etc.etc. Others are doable with little TLC, patience,and superglue if need be for sag.
I have yet to try magic tracks or fruils.