it makes no difference, the form tag just uses routing to generate the url, so if you use @Url.Action you should go
there are even books that use this simple simple tag and URL helper to generate a route
ASP.NET MVC Website Programming is an Example
Edit
** starting with Mvc 4 there is no difference, up to Mvc 4, Mvc 3, for example, require Html.BeginForm to make an unobtrusive javascript check for work
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