Svavar,
I think you are being a little impatient - it isnt as though you mastered Photoshop in a month or two.
I am very proficient at Photoshop - I had never touched Premiere Pro until less than a month ago but I have still managed to put something like this together with a little (actually quite a lot) of effort.
So as to a mask. Select your video go to 'effects controls' and you will square, oval and pen tool masking just as in Photoshop.
Definitely Premiere can be a bit frustrating to begin with - it took me ages to work out how to place a graduated filter on my footage for instance. If you are a 'photographer' you can really short cut everything a lot with 'Magic Bullet Suite' plugin which has pretty much everything in very 'photo' based concepts such as 'stops'. But then again Photoshop itself isnt very photo intuitive.
I think if you plug away at things for a week or two with endless frustrations it will quite quickly 'click'. Photoshop took me 2 or 3 months before I could do very much.