Lee, wait until they're delivered and some miles are on them, then buy the Lionel one. I have the Lionel B6 from a couple years ago, it runs great, has very good sound and smoke, and I haven't had a lick of trouble with it.
I have a pair which are double headed to a wrecker. First is an MTH premier with ps3 and then a Williams which when I got it was severely flawed...the drive shaft [plastic] was warped which caused the loco to oscilate up and down plus ran way to fast...so what to do? I removed motor, drive line and worm gear, installed smoke unit, timing tape on axle gear and appropriate electronics...they puff smoke like working locos, sound from the first sounds like from both...I like em a lot. When parked, Williams is on dead track.