Dewalt a123 vs lipo's

[Hickoryhead]

I have been thinking for a while about these packs. I can get used tons 18 volt dewalt packs for free. Some are worth it others not. I can do the take apart and build but is it worth it? Thats the question. I have not used anything other than Lipos. The reason I do is run time. I don't have to stop a lot to change them. Will a123's be the same way on a MM? or am I looking at 5 to 10 minute run times say on 12 cells? It would be cheaper for me but I hate to stop and change batteries all the time.