Yes, we'll publish a comparison chart when A7 is released. Basically the features will be mostly the same as for A6, but the physics engine and the BSP tree renderer are swapped. Physics will be available in all editions, BSP rendering will be Pro-only.
A7 will take some time, but a prerelease for A6 owners will be available soon. - Yes, you will lose BSP, but you can still use the A6 renderer. However in many cases, especially outdoor levels, the new ABT renderer is faster than the current BSP renderer, so normally you'll gain speed with A7.
The same as before, plus some new features, like distribution management.
Generally, the principle is the same: You won't need the Pro Edition - Commercial will suffice - unless it's a really ambitious project and/or you go for the big money.
Given 3DGS has been a BSP engine for most of its existence I think moving it to Pro is a bit questionable. Some of us have built our long term projects around BSP, and essentially forcing a Pro upgrade to continue on this path isn't right in my mind. However, if ABT is beneficial for indoor levels then it's basically a null point.
My User Contributions master list - my initial post links are down but scroll down page to find list to active links
You switched the physics engine? You meant just that it'll be aviable in std or you meant something like PhysX?