We just traded our 18ec after two years and 16,000 miles of cross country travel. We liked it and my wife really liked the bathroom setup and size. It pulled well and was very solid. Not a lightweight though. My F150 Ecoboost pulled it well and your Tundra should too.
Would have kept it but decided to go with a Fun Finder xt 276, very similar to a Hyperlite 27XL. My new 27 foot Fun Finder weighs about the same as the 18ec. I believe the 18ec and the 21 ul weight about the same.
I was happy wight the Work and Play. It was a good unit from a good company.
Mark and Joanne
2014 Fun Finder XT 276
2015 Ford F150 Lariat 3.5 Ecoboost 4X4 SCrew Max Tow
2011 Harley Road Glide Ultra