I use both, Max and Cararra, and Max is a LOT more ratchet intensive and finnicky then Cararra in just about everything. 
Since it can do a lot more things, there are a lot more ways of going astray in it, and it's much less friendlier towards a new or an inexperienced user then Cararra or Vue are. If you do something wrong in it, there's very little or no warning, and there's not a lot of presets. I was actually floored to find that it's new cloth simulation has about a dozen presets in it, like leather, silk, wet cloth etc... as opposed to just a set of blanks.
I can't say that rendering is any faster, but I never ran comparisons. It's just my gut feeling after having used both.

The nice thing about Max is that it can accomodate a lot of different workflows that happen when building custom projects. I don't get the impression this is important point for you guys (going from Poser to Max).

main reason I have Max is because of it's interaction with Autocad and architectural, construction, industrial segment capabilities which is what pays my bills. If I were concentrating on characters, I'd research tools like Cinema or Maya rather thoroughly. For example, I gather that interposer pro does for cinema exactly what us max users wish to have for Max.
A friend of mine rendered some default settings imports from Poser to Cinema, and they came out looking as good as best poser renders I've seen.
I didn't see it myself, but he swears the rigging came across to.

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