I have heard alot of people speaking on Modo possibly not being the best tool for Archviz/Modeling work. While I do not think there is a "best tool", many are good or great, I do think a few really shine and Modo is one of them. Modo is not just a tool for doing organic modeling. While it does do that well it can excel at architectural modeling as well. Modo can model down to as tight of a tolerance as you want to throw at it. I do not know to many architectural modelers modeling tighter that maybe a 1/16" or a customer who expects tighter tolerances that that either. If someone is saying modo can not model accurately then they have not taken the time to learn how.
I used to say "sketchup does everything I want it to do" too, but the more I use it the more I find myself doing things in modo that I can not do as easily in sketchup. I think we as artists always need to be moving forward...we just hope that our software is moving forward as well. THIS is where sketchup falls short for me. The lack of high poly support is beginning to be a killer for me. So many people want to add good trees into a visualization (stuff like xfrog or onyx trees) and we all know that will grind sketchup to a halt. Yes, there are good work arounds but they will never equal a great full 3d tree. Again, Sketchup is great but if you are looking for a well rounded FULL 3D package then I would spend the money on Modo.
The sketchup importer......Yes it falls short. Much of this is not Luxology's fault though. We have heard this was a matter of Google not working very well with Luxology.
Below are some good video's showing the architectural capabilities of Modo. Sorry, they cost but there are some great models and render examples on the modo forum as well.
http://www.luxology.com/store/training_series14.aspx
http://www.luxology.com/store/15_architectural_interiors/
Scott