Yes i know it's powerfull, but as an architect, images are just one side of my work (actually a small but important one). This is too small so i could give it hours to finetune a render, or a lot of money excepted for big projects. But it's big enough into client decision and communication to make me worying about it.
When i get time i'm really happy to play with mental, but actually i don't even have time to sleep, so the best in this case is maxwell. Why ? because it's setup in five minutes when you're really in a rush and then just hit render, at the end you have a natural lightning effect that is enough for me most of the time (small client presentation on variants or others). During calculation i can make the powerpoint or typing contractual datas that need a lot of time too. With mental you don't have this flexibility.
This is why i love maxwell, and why i really don't care if rendering times are around 8 hours since we have quick preview. Why xsi then you would ask?
Simple, i'm an autodesk user (autocad and revit) but autodesk policy concerning prices for getting autodesk viz are prohibitive 2000€ xsi foundation is doing the job for 500€ and is doing much more actually. The only problem was to get a clean import from revit to xsi (done via dxf >
fbx > xsi). And man xsi interface is way more easy, smooth and clean than max one. It just miss a maxwell plugin

.