Likewise I know someone who left RAMC phase two to join The Grenadier Guards (still serving nearly 13 years later) and also know people who have transferred out of the infantry to pursue a career as a CMT. It comes down to your own expectations and circumstances.
If you want to join the Army to get out in the field, train on a multitude of different weapon systems and generally conduct infantry tasks then joining a Corps won’t cut it for you. Equally if you join the infantry with dreams of being an electrician or vehicle mechanic then it won’t be for you. This is why a good understanding of the various roles will help you.
Ask yourself what attracts you to the Army in the first place, visit their career pages, speak to those with experience, ask questions and form a judgement.