As a brand new diver I shouldn’t really be offering my opinion on equipment, but I have to say this since I saw a very key element in what you posted. You said you were someone who "never felt very comfortable in the water".
Then I would suggest you definitely stay with what has made you feel safe so far and get a mask with purge. I watched several women in my certification class freak out with the ’sucking water up your nose experience’ (didn’t seem to notice it with the men). Because the rental gear we had for class was just basic. I myself had a bad habit of breathing through my nose instead of my mouth before diving class ( I was taught manners) ;) and was constantly choking on a little bit of water. When I got a purge mask, that no longer was an issue since one quick exhale sent everything out of my mask, even the little residual that seemed to want to hang around with the other mask.
I have been looking around as I acquire little bits of my own equipment and there is so much to choose from that I think that basically it just boils down to what YOU are comfortable with, not necessarily what the dive shop guy thinks is the best around.
Angel