I have and use both, too. I think Militec-1 does give a bit more lubrication, but I could be imagining this, based on all the 'net reports of Militec-1 being the better lube. Neither of the two seem to have problems with attracting dust and dirt. Sentry's rust protection seems excellent, I haven't really tested out Militec's. The makers of Tuff-Glide feel that it's safe to use on knives that will see some kitchen use -- that is, ingestion of tiny quantities does not pose a health risk. There is no formal certification of this, however -- for that they'd apparently need to go to the FDA, and the process is expensive, so you're in a believe-it-or-don't situation.
A while back on the forums, someone made note of some chemical or other in Militec-1, that he claimed could be hard on steels. I can't remember the details, but it is a claim worth discussing a bit more. Anyone remember what the chemical was, and what the claim was? I think the claim was made by someone high-regarded on the forums ... Will Fennell maybe?
Joe