SQL Agent is tricky because:

1. If you have only one SQL Agent job being your 'host' you can't run mutliple jobs in parallel

2. If you want to have a non power-user trigger a SQL Agent job from some kind of client you need quite a bit of custom plumbing to get it all to work

Here's another idea: use BULK INSERT instead of SSIS.

But anyway all of these various methods of loading data have already been covered ad nauseum elsewhere.