The team I'm working with uses SVN for keeping version control. (It was used for years by them.) Recently I found Mercurial as a VCS and it looks much convenient for me than SVN.
What arguments wound you suggest most convincing in order to move to Mercurial?
There's Joel Spolsky's introduction to HG, hginit.com.
Mercurial is a modern, open source, distributed version control system, and a compelling upgrade from older systems like Subversion. In this user-friendly, six-part tutorial, Joel Spolsky teaches you the key concepts.
The first chapter is named
Subversion Re-education
He makes a good case, I use Subversion and am very tempted to switch.
Your team either works on a project complex enough to warramt mercurial or it doesn't .... if it does -- you should have felt the chaffing long ago, and so would everyone on your team.
Spell it out to them in their terms. Why would it be better for them, what problems which they currently encounter would be solved by it. Not, on the other hand, what Mercurial does that is better than Subversion. E.g. if it supports distributed repositories yet your organisation has no need for them, then I wouldn't be focusing my pitch on that particular aspect. This is something we can't tell you as we don't know how your organisation works.
You should also consider integration with existing tools, i.e. will it work in the IDEs you use, with the same or better level of usability?
Are you looking at disadvantages of Mercurial over SVN too? A professional unbiased evaluation needs to analyse disadvantages too.
For me, I think the main ones are:
Keep in mind when you are trying to convert them to use hg that some of them would rather kill several members of their family than take 5 minutes to learn a new piece of software.
With this in mind, If you can successfully convert the repository to hg on your machine than you might be able to show them the benefits.
Show them how commiting doesn't mean screwing everyone else. Commiting means 'let me track what I am doing'. Show them how cloning is so fast, and you can have an instant sandbox for new ideas.
Show them that merge actually works.
I say good luck. It is a huge uphill battle to convince people to change their workflow.
If you don't have compelling arguments yourself, then you should ask yourself why you really want to switch.
If however you know yourself what's better in hg than in svn, what feature you would benefit from that hg has and svn doesn't, then you also have your arguments to convince your team and you don't have to ask here.
Just switching because something seems to be cooler without even knowing why is always a bad (ok, very bad) idea.
Assuming your primary reason for switching is likely because Mercurial is a distributed version control system, keep in mind the DVCS functionality is coming to SVN in 1.7 which is due somewhere around the middle of the year: http://subversion.wandisco.com/component/content/article/1/44.html