People want the RCA, mainly because of the cache as it is still considered, because of its historic record of big names and links and location, to be the place to go. You could go anywhere and really flourish, but when it comes to opening doors, the RCA is still the big knocker! That said, Central Saint Martins is also very well respected. I’m not sure on the entry criteria for Central, but know the RCA has a pretty tough entry with portfolio review and interview. I think that ship has sailed for this year as you need to apply early.
I’m sure judging by the date of your original post that you have already reached your decision, but for anyone reading this with the same quandary, there is another option. If you are not interested in the qualification or didn’t manage to get on a course, you can still go travelling and visit lots of places where you can get experience. I went travelling to New Zealand several years ago and did WWOOFing, which stands for willing workers on organic farms. Despite the title, what happened was that I signed up and was given a book of 800 places to stay in NZ where I could work. You don’t get paid, but you get your food and board for free. If you work the morning you get the afternoon off or work a whole day and you get the next day off, what ever you negotiate. You have to be under 30 years of age. The reason I mention this is that I travelled all round NZ for very little money and only stayed on a farm once. I lived and helped a basket weaver, stayed with someone and learnt to carve bone jewellery, met plenty of artists who had access to pottery wheels, I made furniture, built a turf roof. I could have gone on a 2 day workshop to forge a carving knife but didn’t. There were plenty of options, which may be food for thought. Just about every country does WWOOFing, so the world is your oyster.