Torque Game Engine is a good tool, plus it's multi platform (PC, Linux(TGE), Mac(TGE), XBox 360 (TGE will work on it and so will Torque X) and very recently Wii) As for the MMOKit, I don't know what platforms it's for (I haven't got the MMOKit), very likely just Windows. Scripting I've found slightly difficult, and you can edit the Torque source code if you want, though you'd need C++ knowledge to do that (I've had trouble implementing a sword feature this way) - Good news is, the MMOKIT will have Melee built in.
You can sell what you make with Torque as long as you have bought the license to do so - the demo and 'kits' you can probably make a full game with - but wouldn't have the ability to sell legally or have access to documentation/resources.
One downside is though, Torque uses a specialist file format for 3D models, well 3... .dts is a normal 3D model, .dsq is an animation of a .dts file and .dif which are map or 'interior' models - much like the kind you make in 3DWS. There are .dts/.dif exporters for 3DSMax, Maya, Softimage|XSI, Lightwave, Milkshape, Blender and good news is you can make .dif files with 'Torque Constructor' which you can download from their site for free. (Other .dif apps include Quake Army Knife (free) and 3D World Studio and deled)
I bought it a year a go - unfortunately just too early to get the free upgrade to 1.5. This is probably difficult to script with to start, but then I've never scripted in anything before - but as I've been using LUA in DBP Torque script seems to make sense more:
Just to give you an idea here is a trigger I made yesterday - it's a simple on at that:
datablock TriggerData( MyTrigger )
{
//This is the period by Mili seconds by which the tick trigger function runs
tickPeriodMS = 200;
};
function MyTrigger::onEnterTrigger( %this, %trigger, %obj )
{
TextAll('Hello I am a Trigger. Something may happen when you tread on me...');
AIPlayer::spawnOrc("Viking", 1);
}
function MyTrigger::onLeaveTrigger( %this, %trigger, %obj )
{
Parent::onLeaveTrigger( %this, %trigger, %obj );
}
function MyTrigger::onTickTrigger( %this, %trigger )
{
textAll('Calling all Nutters!');
Parent::onTickTrigger( %this, %trigger );
}
With it, you have to understand your game technically is already made, the game .exe is already there with all your engine features etc. so that means no compiling (unless you pull up the engine source into C++) The engine is set up like an only game, as you have the client and server sides...for offline games you can still use the server side as a virtual server for ingame action etc. (which you can't do on the client side) - my code snippet runs on the client side - when I make a trigger with the datablock 'myTrigger' the function may be called based on the player's collision with it.
All you really need to do is level/gui build, edit scripts etc. which is a lot harder than it makes off to be. Hence I'm still using DBP as my main product.
As for Realm Crafter I've seen good looking results for but I look at it with a hazy eye.
[edit]
An Alternative that is free - there was a community project called Realm Wars being made in Torque 1.2 (It's editor features look dated in terms of GUI but you could make a good mod out of it) you could mod the scripts with its engine features - it has multiplayer support Melee and Projectile weapon, magic spells, a basic inventory, CTF and Deathmatch modes and plenty of media to play with (two character models and scripts - Elf and Orc, weapons (Axe, Sword, Crossbow, Longbow), Spells (Fire, Fire Charge, Ice, Heal, Invisibility) a shield and the mods should provide you with a larger choice of crossbow scripts, there are numerous level objects as well)
Check out their archives if you're interested(there are a few mods on there as well) - downside of course if you probably won't be able to sell what you make:
http://www.rw-archive.com/news.php
Plus it might help you see if you like scripting in Torque.
[edit 2]
Of course there's something Much Much closer to home...the Open Source MMORPG project - just keep an eye on all of their source code and use it in DBP.
Hakuna Matata