REME or Royal Signals

I served in the REME, so have a bias.

They have different roles. RSigs are responsible for the Army's operational communication systems and Electronic Warfare (EW) capabilities. The latter means that RSigs are considered as one of the fighting elements of the Army. RSigs have also taken on roles in cyber, IT, etc.

REME are responsible for repairing and maintaining the Army's equipment. The REME repair everything from rifles to main battle tanks and helicopters. The majority of REME are based at 'first-line' i.e. they are posted into infantry, armour, engineers, where they repair the kit that those units have. This means that REME soldiers are more widely posted.

I'm assuming that you are looking at some form of electronics/technology role. Both Corps can offer this. In the REME these would be Elec Tech and Avionics Tech. The latter is an Electronics Tech for Army Aviation (Apache, Lynx). Technicians from both Corps are generally very employable in civilian life.

If you want to find out more, a good approach would be to be if you can get a familiarisation visit to one or both Corps. They have recruiting teams who are generally a good source of information. Ultimately, you will have a gut feel about which you prefer. Follow that. If you later decide that you want to transfer to another part of the Army, there are processes to do this.