I just downloaded and read the owner's manual for the Platinum and here are my thoughts.
I like the fact that it is solid state without any knobs to allow for the infiltration of dirt and water. I also like the light weight. that makes swinging so much easier than accelerating a heavy machine.
I do not understand the arm strap however. If the ergonomic design of the Platinum requires an arm strap, I would pass. When I'm out MDing, I am repeatedly getting down and using both hands to deal with the task of excavating and I certainly don't want to be burdened with an arm strap.
I read on pg 20 of the owner's manual that the numeric display system is correlated to pretty much the same categories as are displayed on my Elite 2200. So I wonder why bother with such precision when iron can appear as silver. It is much akin to using a micrometer to build a stick-framed house when a tape measure would be more efficient. I think it is a sales gimmick to be frank.
The no-motion pinpointing function is a great feature, I wish my Elite 2200 had it, however after practice, I found I can use motion pinpointing to precisely locate targets just about as fast with my Elite 2200 as I can using my Pioneer 505 in no-motion mode, plus I don't have to alter any controls to do so which speeds up the process.
The advertised depth on a US quarter is the same as as the Elite 2200, which is 9 inches. On a US silver dollar, my elite can detect at an air-test distance of 9.5". So my assessment of the Platinum is that it beats the Elite 2200 in the fact it has no-motion pp but not much more. Keep in mind that I don't know the recovery speed of the Platinum. It may be superior to the Elite 2200 in that regard.
I have seen the Elite 2200 for as little as $120 new in the box. The "regular" street price is about $150. If the Platinum is much over $175 I would pick the Elite 2200, unless the recovery speed of the Platinum is markedly better than the Elite.
Mark