Msd used ignitions

looking to upgrade my ignition system sometime, and just wondering. msd claimed the msd 44 to be the end of all ignitions, yet I still see used, refurbished, old units that have failed, or thought to be failed up for sale. as with all electronics, is it wise to buy this used/abused parts, or just buy new and get it over with? I always here of how teams switch all the mag stuff when they cant find the problem and wondering why it cant be tested by the manufacturer for problems. this goes for coils, and boxes as well. any ideas or info on this?

 

Buy new parts in this area because it is MUCH less expensive.