I have a Big Shot and I found most sandwich recipes out there recommend using tab 2 of the platform. When I did that, I got the embossing marks too. So I experimented with CS shims and having the platform open at tab 1 and I've found what works for my machine.
I use 5 pieces of thin CS as shims with the platform at tab 1 - I get perfect cutting every time now, no embossing marks! I also use tab 1 and the same 5 CS shims when I emboss with my Nesties - and I get perfect embossing results. The CS I use is nowhere near as thick as SU! CS - it was just thin pearlescent card I had in my stash that just happened to be the perfect size for shims. I added a piece at a time until I got the results I wanted.
I'd say try experimenting using tab 1 on the platform and adding CS shims until you get perfect results with your particular machine - rather than getting a new one! Good luck!
