> Up until now, I have been using spreadsheets for this kind of thing. That works fine for charting, but not much else.

Historical archives! http://i.imgur.com/RsB99dN.png that's one thing that's always kept me off of services, not being able to export my workouts, so I made sure you can do it in CSV, Markdown, and bbCode (individual, date ranges, and all workouts).

If you want to give it a whirl here's an invite code w/o needing to wait - https://thesquatrack.com/register?c=nn5z3za84d