TT and Cart for new phono stage

My Gram Amp II SE calls for a cart with a 2-10mV rating. Graham Slee also suggests the phono stage will accomodate both mm and mc. My local dealer suggests 2 options.
1. The Clearaudio Arum Beta mm cart fitted on the Emotion tt.
2. A Benz Micro Siver mc on a Robin tonearm, fitted on the Champion table.
I am considering both, however I am reading rave reviews of the Dynavector 10x5 on the Rega P5 ! What's the 10x5 sensitivity?
Is it safer to go with a 4-5mV mm cart than a 0.9mV mc cart?
I do not know what to do.
P.S. I will be using an ARC LS8 MK II pre amp. Help?
I can't be a lot of help but I will say that higher output is better unless you are in the mega buck pre-amps. $8000 and up for great brands and $15,000 and up for bad brands. (yupee audio) Your dealer sounds like he knows what sounds good so I would trust him. The Benz is awsome for the money and even though I am a Rega Tonearm fan I am less the thrilled with their tables.
Thanks Duane, funny, I am leaning towards the mc Benz Siver and Champion table...