I'm not a medic, but having dissected a pigs heart at college, I found it brought to life (pardon the pun) what we had been learning about.
I guess closeness to death and learning how to deal with that would be an advantage.
Speaking from personal experience, I didn't find there was as much to gain from it as I had initially thought. We had prosections about as well as dissecting and the prosections were obviously better dissected, much cleaner and more representative and therefore better to learn from. Dissection I found wasted time for no good reason (without being disrespectful to the cadavers), and I really didn't see any advantage when compared to the prosections, except maybe getting an appreciation of the layers of the body and how deep some structures can be. With regards to surgical skills/tools, because the cadaver is not alive (and there's no risk of killing..) I think you'll find technique goes out of the window after a few hours (to get to the structure within your time limit), so I don't think you should think of surgical skills as an advantage at all - surgical skills will be taught later in med school.
As someone above rightly pointed out it also depends what you're comparing dissection to. If you're comparing it to nothing, then ofcourse it's more advantageous. If you're comparing it to prosections, I'm really not so sure. In short I didn't find anything overly advantageous about it, and I would think twice about going to medical school X over Y purely because of dissection.
The above are my opinions only ofcourse and I'm sure other people have different opinions..
I didn't find dissection particularly helpful. As people have said, you just get given a body, the tools to dissect it, and if you've brought one along, a book. It's enlightening to see how the body fits together and see the actual organs, but I think that prosections and actually just reading the anatomy books can help you with that. Most of my anatomical knowledge in the end is based on visualising how things looked in books or on models. I've never once had a flashback to dissection or thought 'oh yeah, that's what it looked like!', and am not convinced it helped me remember anything. It was just a very unusual life experience.
IMO models, prosections, that plastination type stuff and importantly 3D computer software would be ideal.
About the only thing where I think dissecting a cadaver > prosections is that you discover the secret life of fascia and some of the conceptual body cavities which can only be seen when you look at the body as a whole, I think. Generally fascia etc. is peeled off or generally hard to conceptualise on a prosection, because you can't see where it linked up to.
Perhaps it depends on you as a learner but, with the greatest of respect to the people who donated their bodies, I don't think it was a useful exercise for me. As mentioned by others, I don't think it's an essential opportunity to have or to make choices based on. If you do it, fine, if you don't then I don't think it will hinder your ability to learn anatomy, pursue a surgical career or whatever you want to do.