welcome gtanse..
it looks like the 2005's all have B&S or kohler motors..
Link to simplicity specs..
http://www.simplicitymfg.com/s_regent.php
FYI: simplicity is now owned by B & S and so i would think you may see more B&S motors in the future.. Massey & Snapper are also owned by simplicity.. basically the same tractor.. different name..
The regent is a great LT...
Honda used to make lawn tractors but stopped 4 or 5 years ago.. they do still make motors.. nothing wrong with a honda motor that i am aware of...
Again.. the regent is a great LT..
What are your needs? just cutting? snow throwing??