Hi Peter, welcome to the forum. The answer to your question is that you most likely will not be able to use your existing controller, especially if it does not have Motorola Marklin as one of its protocols, as this is what most Marklin locos understand. Marklin also has a new protocol called MFX, which only the Central Station uses. I believe Trix locos use DCC. If you want multiprotocol, then use either the Ecos, or the Intellibox - both use Motorola Marklin and DCC, but neither have MFX.
If you are going to use exclusively Marklin, then go for the Central Station. Cheers.

You could use your Powercab with Marklin, if you were able to replace the decoders in the Marklin locos with the ESU Lokpilot / Loksound series of decoders, as they understand bothe Marklin Motorola and DCC. However, you may not be able to replace the decoder in all Marklin models.

Lars, the Powercab is DCC, that's why I alluded to being able to use DCC if the standard decoders in Marklin locos are replaced.

I'm not that familiar with Trix, but am aware that they are mainly DCC locos (see my post above - "I believe Trix locos use DCC".) - the Trix Central Station is DCC is it not?

Thanks for the replies gents.I am leaning towards M just for the amount of items one can buy so i may have to bite the bullit and sell the powercab