I know this is a bit late to the party, but I use quite a few products from both of those lines, actually. I have to say that the sleeping peel line from bliss seems to have cleared up my skin near miraculously. While most people wouldn't have considered it bad (a couple breakouts a month, lots of those deep, painful types) I can't really remember the last time it happened.
The two Bliss products I've used nearly every day and haven't changed at all are the Sleeping Peel Resurfacing Gel and the Sleeping Peel Serum. I used to use the Steep Clean Moisture Lotion as well, but it got really hard to justify the cost of that compared to other moisturizers that seem to work as well. I've also got a few of the Bliss masks, which work wonderful, particularly the Instant Mattification Deep Cleaning mask.
The Mario Badescu, I've only recently started using, well, a few months ago now, on the recommendation of a friend. I started with the Whitening Mask (I loathe my freckles), and I loved it. So I got a few of their moisturizers and the Glycolic Foaming Cleanser. The cleanser I love. It manages to clean my face without overdrying, which is a first for cleansers. I did notice that it was a little drying if I used it more than 2 times a week, but my skin is a little on the dry side, so it may be a good option for you.
Their moisturizers, while working as well as the Bliss I so loved, leave me feeling sticky until I put my makeup on (or wake up after a night application). It's not worth it to me to spend the $20 extra for the Bliss, but it's the only complaint I have about the products I've tried so far in the line. I haven't tried any of the moisturizers for oily skin, though.
All in all, they are my two favorite lines of skincare products, so either choice is pretty brill, if you ask me.