What I saw from their forums is that they complained indeed mainly about docs and about some bugs. And another problem of the users is that they did not keep their promises.

From a commercial point of view Ratchet is right. They lost their track to support indies, tried to address professional developers with higher prices and better technology. But the tech did not grow fast enough and not mature enough to reach that goal. Besides that the Instant Action platform did not succeed as expected.

Currently they all hope that somebody buys the Torque asset.

but why should anyone buy it? doesn't it have a kind of bad name/reputation now? i often read that their source code isn't that great either quality-wise. what would be the advantage over building a game engine around ogre for example?

I like very much Leadwerks but is it really so slow as people say ?
Did anybody make a comparative 3dgs, Unity3d, Leadwerks ?

In leadwerks, stuff like ssao are always on by default so it's not really comparable unless you use the same shaders in all engines.

Actually Leadwerks is quite fast, can render terrains with millions of trees as an example. What I dislike personally is the workflow, the tools, the usage of different scripting languages for everything (material, physics, scripting). Thus it looks a bit inconsistent to me.

Nevertheless, the results are great, it renders objects very nicely and fast and it is powerful in terms of capabilities.

Maybe I like it because I come from Blitz3d ( before 3dgs )
Leadwerks set of commands is quite similar
Moreover I still prefer the traditional 00P hierachic style over the new " components " phylosophi
A matter of taste of course
However about the speed I have my doubts
I have a one year old desk top , an other five or six years old desk top and a two years old lap top
I downloaded Leadewerks and Unity3d demos
Unity demo ( The Island) runs fast on all the three PC's
Leadwerks demo is acceptable but I would not say fast, only on the new desk top

I accept that , as Quadraxas said , In leadwerks, stuff like ssao are always on by default but frankly speaking I dont see that advantage in terms of visual quality

Did anybody make other comparative test ?

Same here. I tried Unity, but it's not my favorite style. I also like the traditional OOP. (working with Delphi since many years)

One reason more to hate the current situation of InstantAction/Torque because Torque/TorqueScript has also the OOP-style.

That of course can cause some problems with modern technology. Leadwerks just like Unity and most of the big commercial engines use deferred rendering now. This is fast, when you use different lights and many shaders at once, faster than old forward rendering. But it also requires shader model 3 (available since how long, since 2004?). So on modern and moderate aged hardware it is just the better solution.

But when you have stone-age hardware, then Unity scales better for sure. It can downscale from deferred lighting, to forward lighting, pixel lighting to vertex lighting and even harmonic spherical lighting. Thus it can not only render on very very old hardware, it can also run on different platforms, mobile devices and consoles. This scalability is even part of their rendering optimization. When you have 8 lights visible at the same time as an example and you dont configure them all to be "very important", then Unity renders only the nearest of them as pixel lights, a few will be vertex lights and another few harmonic spherical. So it still renders faster than most engines forcing all 8 lights to pixel lighting.

But this also shows that you dont have the same quality on each platform. It might render faster on your 6-years old PC. But it also scales down to a lower quality.

I was expecting Leadwerks to be slow on old hardware, the point is that it is slower than Unity3d even on my modern PC
Moreover I used Unity3d and Leadwerks demo's
I suppose that demos are optimized for the engine

But the demos of Unity are not that demanding. The bootcamp and the island demo are using quite small textures, only a few lights and moderate shaders. But they both show some bigger scenery. The bootcamp demo even uses the new technology from Unity 3 for a smooth transition between realtime lighting and lightmapping. So everything that is a few meters away does not use real-time lighting anymore. Leadwerks does not do anything like that, everything is realtime.
The bootcamp demo also uses the new occlusion culling in several areas and the terrain has no normal maps at all.