Hi, take a look at this page and watch the video. It is integrated and pretty great 
I bought it long ago, was beta tester. Not using it much these days, but hands down it has one of best material systems I worked with.
I digged through the thea forum usergallery, but I still cannot find real good renderings.
They lack on realism, they are not crisp, lighting is flat, maybe I’m expecting to mutch.
I find Corona much more convincing.
Kind regards
Alain
Did you look at these? http://www.thearender.com/forum/viewtopic.php?f=21&t=6183 I’m not sure where you’ll see much better outside of big studios. Remember Thea is currently on sale at 195 Euro, I honestly don’t think it can be beaten on the speed/quality price ratio. I also own a V-ray license, it’s another good option for Blender users but I wouldn’t necessarily recommend it over Thea.
That example is also not really good (shadowareas are to dark, it’s like light is not going enough into depth).
I know a few big studios, but they all use V-Ray.
Never saw a real good pro using Thea Render.
Convince me by the oposite and will give Thea a try ! 
Kind regards
Alain
so why bother using blender? No big studios use it
Alain, did you google Thea Render and look at images? You have to consider most of the best architectural work is not displayed in public due to client disclosure agreements. That’s about 85% of my work.
What is it you are looking for? Why don’t you convince yourself and try the free demo instead of judging from what other people do. I see plenty of what I would call noob 3d work come out of the high end “industry standard” programs more than what I would call professional, but that don’t stop me from trying different tools to see what I can do with it. If you judge a program by user galleries, you miss the whole point of the art. You seem to be focused on the wrong things. Look at the programs tools and see what you can do with it as an artist. (things like bucket rendering, channel pass variety, speed etc.)
I personally see a LOT of impressive renders made with Thea. We are all entitled to our own opinions but maybe you should just leave it alone if you’re just not interested. In that case your opinion means nothing here. Show us an example of what would impress you so we can judge 
Here’s one example of an old Thea Render that was done without all the new features added since.
http://www.ronenbekerman.com/thea-render-1-1-review-by-sandro-sorce/
There’s plenty more…just use google.
@Mistro
Highendquality architecture renderings do for example Peter Guthrie and Bertrand Benoit, both use V-Ray.
The Thea Example on Ronen Bekerman’s Blog is the same as “seanser” did mention.
I’m a little bit tired of testing other renderengines, the most look promising at the beginning until you use it in your daily workflow…
@Bernardo
I like Blender more than Max because it’s UI feels better to work with. But to have an economic workflow in the CG industry you can not ignore Max/Maya/Cinema4D/… But that’s offtopic.
I’m confused by the website; all I see are links to download / purchase pages for v1.3 (?). I must be missing a button somewhere…?
The download link for 1.4 is in the portion of the forum for registered users at the moment. I presume it will replace the external 1.3 links soon.
That’s one of the things the developers have failed so far - to get names like Bertrand Benoit or Peter Guthrie and so on to use Thea and publish some nice pictures. I think Thea is so feature-rich and till 1.3 “rock-solid” that every good artist can bring it to the same level as any other engine.
I tried it and loved it - because most of it was understandable for me and I did get much faster good results as with VRay.
Try it and then judge it.
Even the 1.3 which is the engine which you get with the demo you can see clearly if the shoe fits on your toes. (Don’t know if you understand what I mean with that, I’m german…).
Yeah. I always like seeing his posts. Very talented.
No sorry, still the same: Shadowareas are mutch to dark (it’s like missing light), it feels artificial. Especially in the nightshots the tonality is to black/gray (night is not black it’s blueish) and makes it feel unnatural.
I think it is just way how it is tonemaped.
It is personal taste, someone might say that is artificial to have too bright shadow areas. I see Vray tutorials and almost every postwork has S curve applied (to make shadows slightly darker) because GI has tendency to make it bit brighter than it looks in nature.
Are you critiquing the software or people’s work? And by the artists works judge the software?? Makes no sense.
@Alain, I thought we Blender users would know firsthand that it is the artist, not the tools, that make our artwork great. If you seriously judge the software based on images made by random people then you have missed the point completely.
Other people have pointed out numerous times that there is a demo that you can try for free. If you don’t even try it then you have no right to comment on it.
Thea uses the same GI and BRDF functions as every other physically based renderer out there. It just does them in a novel way (including their Field Mapping, which is pretty amazing). Things like final darkness of shadows and color have very little to do with the actual renderer these days. The reason for working in a linear pipeline is so that you can tweak these things properly in post.
This guy has some nice renders LINK .
Impressive work !!!
he he, my good old friend “solo” (Pete).
An old experienced user of a Kerkythea clone named “podium” (integrated to sketchup).
A very talented artist IMO.
Even Kerkythea (which is free BTW for those who don’t know) is a great render engine. Should it be called the mother of Thea? I think development spawned from it. Don’t quote me though. But I can say that I’m using Thea in part because of my experience of Kerkythea.