What I really like about subcontracting, is that you are not carrying the full risk for the project. However, the client is still the client, and this carries with itself both a freedom (no loyalties beyond the contractual) and an added responsibility (it's your client, and you want them to be happy).

It's a style which suits me, and gives an added motivation. Note that if the work itself is extremely boring, this still doesn't make it all hunky-dory. There must be a balance here.

Personally, I like the smaller-sized projects where the iOS part can be done either by myself or with another team member. This way, I have enough overview to wrap up the project in a decent time and look for another if it's not to my liking.