For me the Orion ON1-H is perfectly designed. I love this sculpt and would like to see more Mechs designed like it. It has a fantastic amount of detail, only a few pieces, and there is no guessing as to what piece goes where; all of the pieces connect to each other in a different way. There is no confusion. Some people might decry the lack of "poseability" but for me it isn't a problem. I don't want to have to spend a hour cleaning up pieces, figuring out where they go or using tweezers to put small pieces together. It is too much of a hassle. Plus, I would say take a look at the multi piece Mechs up on Camospecs. Most of them are configured in a static pose anyway.
The Mech versions of the Spectral LAMs are the exact opposite of the Orion and a perfect example of what I dislike. They have so many pieces that you need instructions to put them together. Sure they look great in the end but I buy the mechs to supplement my gaming experience. If putting them together becomes to much of a chore, then I won't buy them.
Just my thoughts. I'm sure some will disagree but the ON1-H is perfect.