Has anyone compared SPG and Marriott Rewards? I understand every program has its pros and cons. I simply want to hear your inputs to help me make a better decision.

I'm Marriott Rewards Gold (reached by getting 15 elite nights from the credit card). I got the SPG Platinum challenge offer, which would give me Platinum if I stay 15 nights in the next 90 days. With my current travel schedule, I can do it, but would have to choose hotels a bit further than I could do with Marriott for my next 2 destinations (Burlington, MA; Pune, India). Also, by doing so I would jeopardize my Marriott status this year.

What do you think? is it worth it?

I like Marriott Gold / Platinum status, for its lounge room access (free breakfast) at most Marriott Hotels. Does SPG Platinum offer anything similar? I can't seem to find it on SPG program page.

Thanks!