The numbers you quote look in line with what I would expect, especially if you are getting close to a market rate salary. They are profitable and funded, which is a big milestone. It would help to know - Are they paying you a market salary? What is your past work history like? Does it include startups, and if so, in what role? How great is the rest of the team you are joining?

The Mark Suster link mentioned by brudgers is solid. My suggestion is to examine your motivations and goals, and then to be true to them. It will also help you evaluate your progress against those goals.

I'm going to presume this is your first startup, so these comments may be wildly off base if it isn't. The things I got out of my first startup were these:

(1) Money (we actually went public, though I had a very small piece of it). (2) Massive rapid skill development in circumstances where I could take on as much responsibility as I wanted and could learn from great people. (3) Connections to people that pretty much set me up for almost every job I had after that.

The value of (2) and (3) were huge. If I could give advice to my younger self it would be to focus on those two things first, then negotiate the best financial outcome that I could after maximizing those elements.