I've gotten both and each one is for a different use... The deep tissue, depending on who does it, hurts like hell while you get it but then feels better long term. If you don't have any pre existing issues that need to be taken care of I would go with Swedish before Deep Tissue.
I have a hip problem that causes all sorts of muscle issues because of how I walk so I go in with specific problems that need to be helped.
You sound like you are getting this for relaxation...
I would go for Swedish if I were in your shoes.
Either way, you will feel SPECTACULAR when you leave... There is nothing better than a good massage.
Oh, just don't freak about the nudity. The person massaging you has no interest in how you look... they are there to do their job and it doesn't matter if you are a 90 year old obese person or a 19 year old super model... This is their job... They've seen everything and you are just a customer.