The user interface of terragene as well its functionality are really good! There's nothing that I dislike about it so far except maybe some minor bugs here an there but they will be fixed soon enough :) If you have never used terragen before then this software can take quite long time at first sight because all settings need tuning up until everything gets right in place (like how light works etc.).
It takes sometime till things get better after which we see amazing renderings like no other renderer out their! You wont regret giving Terrain Engine A try ;) We were looking forward towards using Terrgen since last year when our client requested us such renders & simulations with 3d models created by them via photogrammetry approach - basically shooting pictures around buildings/buildup areas where people live / work together remotely through video conference tools e-specially during COVID situation :).