Welcome to the community.
1. RSA - do you mean RSA for authentication? That is one of several authentication schemes that can be used with AnyConnect. Others include local user database, Active Directory, RADIUS, TACACS, etc.
2. It depends on what they do once they log in. ..and on your available bandwidth .. and on your head end device's capabilities.
AnyConnect and related products can be a lot of material to digest but I recommend you set up a cisco.com login if you haven't already and take a look at the product support page here. There are quite a few informative documents. Also look at some postings in the documents section of this forum.