I've got the Mini 3D, and except for the servos stripping out, I love it. For a 100% nuttin' but 3D pilot, the HS-81s are good, but for flyin' pilots, the HS-81MGs (or85MGs) are better. The 81s have the torque, but the tiny plastic gears are not up to the task. I think the MGs will hold. The Magnum 25 would do well on the Mini 3D. Mine has a 25LA, and has plenty of power. Your Magnum should be a bit stronger than my LA. Try a 10x3 APC.
I just yesterday ordered the Profile Edge 540T, I'll have to get back to you on that one. I have not read any negative comments on it, yet. As for the engine choice, I'd say any high performance 46+ is good. If I right now found myself in the market for a 46 two stroke, it would be the OS 46 AX. That is said to be a heck of a machine, perhaps even out turning the 50SX. I'm also convinced, from reading, that the Webra 50 is a little screamer with a 3D prop. There are many supporters of that engine for fun fly 3D. Shoot for an engine that weighs anywhere from 16 to 19 ounces (with it's muffler), plus gobbs of power, and you should be fine.
Well, I have now flown both. I put probably 12 or so flights on the Mini, and perhaps 6 or so on the Edge. I gotta say, if the big bad regulation man came to take one away, I'd hate to have to pick one to go. It is not an easy choice.
As for bang for the buck, the Mini is the deal of the decade for 3D pilots. With much better looks, and truly unlimited performance, the Edge is an airshow waiting to happen. Both draw a crowd once the nose gets above the horizon. Most people look at the Mini, but study the Edge when on the ground.
If absolutely forced to choose only one, and asked why I did it, I'd have to say go with the Edge. Sadly, better looks is the greatest difference. Both are amazing to fly.
The Edge with a hot rod 46 to 50 will make any 3D pilot a very happy pilot, indeed.
There, I did it. I made a decision, but I'm glad I now have both...