One requires a dedicated server that supports IMIs and the other requires a permenant MySQL/PHP-enabled server. Either way it is insecure and either way it should work, so go with the one you know better (or make a dedicated server in Jamagic). I can't really comment further unless I know your plans, but I don't really like IMIs (although they are probbably easier).
I think it depends on how big your database is going to get. While it is small, an IMI would give you better performance. As it gets large, howerver... IMI would probably become a nasty bottleneck.