Considering T3D, price + source over UDK or CryEngine 3 SDK

#1 Since you get source the answer is always "YES!" to everything. But there's a qualifier; you also need the skill. DX11's main features aren't all that, really. There are a few things which might be nice to make use of behind the scenes for optimisation (as is always the case with new graphics tech), but the obvious ones are a few new fancy effects that help a little towards realism when you're lying face down in your own blood and have time to actually admire the graphics :)

You'll probably also have to delve into every part of the rendering engine to implement new shaders and new APIs. But you can have a beautiful looking game with DX9 tech as long as you have great artists.

Lua? Yes, it'll be hellish. But many of us have been nagging GG to replace TorqueScript, either with a redesigned TorqueScript done right, or another, faster language. I think they're well aware of the need, and we might see something down the line. So adding Lua would not be fun (you'd want to circumvent many core parts of the engine to do it *well*), but it's very doable.

#2

Quote:able to implement Lua?

may be in resource section there is already an addon for lua support

#3 Ah, that's excellent! Saves me some time on implementing.

This is probably been said over 1000 times, but how does torque stack against unity? While with source everything changes as I can strip DX9 for DX11 or use another render or a custom one.

#4 I think it stacks up very well against unity in general, but it's just a different philosophy. In my opinion, you get results much faster with unity, also the amount of documentation and learning materials for unity is much better. A big plus I think for unity is scripting in C#, as it is a much wider know language than TorqueScript.
On the bottom line, I think you need to identify what features your game needs exactly and then evaluate the engines to see which one fits your needs best. If you're doing some FPS, T3D is for sure a good choice, as it comes with lot's of features that you first would need to implement in Unity3D. However, if you are doing something completely different, then it might be easier implemented in unity than in T3D.
Difficult to give some final advice, but what speaks for T3D is for sure having source code, which allows you to modify basically anything, if, and that is a big if, you have the skill to do so in C++. Besides that, the price and no royalities are definatly a huge plus. Unity3D sets you back much more, but gives you more platforms.
And well UDK is very nice, but the royalties are huge and probably a killer item for many people if the goal is to get a decent amount of money out of your game.

#5 Before I click the Buy Now button, what's the current state of the world/forest editor, FX, Vegetation, water density(water rendering or whatever you want to call it).

I'm still looking at CryEngine's Sandbox 3 editor(which currently is DX9/10 for the SDK) which I've produced some pretty realistic forests and islands.

One other engine I was looking at(as it's close to CryEngine and Torque) is S2 Engine HD. It looks to have a pretty intuitive editor but that's just judgement from youtube videos from the company.

#6 Erick, I think you can download the Demos and play around with the editors there. T3D can definatly produce nice visuals.

#7 I'm not sure what the end-goal is, but note that CryEngine's free version is only for non-commercial use.

#8 Also, adding on to Dave's post, um there will be a MS DotNet scripting interface in beta by the end of the month.