My office uses Maxwell Render / http://www.nextlimit.com/maxwell/
which touts itself as 'the world's best in realism'.1) Is it easy to learn?
essentially yes! It works differently to 'traditional' renderers as MR is based on real world settings so you basically add your lighting or choose an environment, materials, pick a camera and render. For novices, you'll get okay results with a minimum learning curve as the software pretty much does most of the hard work. Going to that next level of ultra photo realism takes effort to understand what it can do and how to work it. This is where the tutorials come in handy. It interfaces with DataCAD through 3DS or DXF export and imports DataCAD entities easily. Ideally, it works best with dual monitors as it allows you to expand the interface and place more of the menus on the second monitor, especially the materials library. A useful feature is the ability to create unlimited images after rendering is completed using its Multilight software (built-in) and as a free standalone software. It also allows you to stop a render, then resume at some future point, which can be the day after or later as you get time. Check your hardware is up to speed for best results. The licensing is similar to DataCAD in that once you've paid your subscription you can continue to use it indefinitely with the option to upgrade to the latest version, unlike say Autodesk products which expire annually and need repaying to use,2) Is there good tutorials, written or training videos, to learn the software?
in the early days (2010 and before) it was hard to locate good tutorials but now there are plenty: https://www.youtube.com/channel/UCp3pJS ... -h57lLSGxA
(free materials), https://forum.maxwellrender.com/
...just do a Google search and you'll get pages of independent sites,3) What would you like it to do better?
Improved speed. We're on v3 which is CPU-based with v4 now working on CPU and/or GPU for extra speed plus it includes a de-noiser for additional sampling. Our current specs are Lenovo WS Win10Pro, 8-core 2.6GHz Xeon CPU, 96GB RAM, NVIDIA Quadro - depending on the scene, external renders can be from 30-60 mins. to a sampling level without noticeable noise, to 8-12 hours for a quality interior with artificial lights down to an hour or so with natural lighting. You control the time and quality so you can render all day or just an hour depending on the quality you want to see....which is dependent on your hardware!4) How much does it cost?
The software is out of Spain so see their web site for US dollar pricing.