Well I bought it several days ago (and beat it the day I got it). I didn't think it was going to be that short. Anyway, it was good while it lasted. It wasn't worth $20 bucks. The episodes should have been $15ish so they would be close to $50 together so they'd be equivalent to a regular release combined.
Kind of a spoiler (if you haven't beaten the end):
I agree about the ending part. It was ok fighting the strider, but it wasn't anything hard since you did that plenty in HL2. The repeated escorting was riduculous. The very end on the train was nice though seeing the scenery change.