I completely agree with better than "replacement level". I might even go as far as to say that Thompson is close to being a "solid NBA starter". But I can't agree with "one of the best rebounders in the league"
I looked up players by rebound rate that played more than 500 minutes last season.
http://bkref.com/tiny/1IUz7
Thompson comes in at #44 in the league with an RBR of 16.3. That's decent, and it's good enough to be better that guys like Zeller and Bennett, but Thompson was closer to those two weak rebounders than he was the strong rebounders like Love and Varejao.
#9 Anderson Varejao 19.6
#18 Kevin Love 18.7
#44 Tristan Thompson 16.3
#63 Tyler Zeller 15.1
#91 Anthony Bennett 13.1
Here are the top 8 in the league. RBR >= 20.0 will always put you in the best of the league.
#1 Andre Drummond 22.3
#2 Omer Asik 21.7
#3 DeAndre Jordan 21.6
#4 Reggie Evans 21.5
#5 Andrew Bogut 20.7
#6 DeMarcus Cousins 20.4
#7 Dwight Howard 20.1
#8 Gorgui Dieng 20.0