Reserves: Royal Marines or TA

Second year uni student looking to join the reserves, was looking at either joining the royal marines and maybe going into combat engineering or do a engineering role in the TA.

I'm trying to gather as much information on both options. What's the difference in time requirements and financial support & pay? If it's mostly just weekends should be fine. Fitness isn't really a factor as I'm already in decent shape, I know the marines is more demanding.

How much time will you be mobilised each year and will it conflict with uni? I was hoping to get my driving sorted as well can this be done in the marines I know the TA do it in a lot of their engineering roles.

Any extra insight or information would be appreciated.