I've been tracking Diono Radian RXT for several months. Albee Baby is running a sale on two colors:
Radian RXT Graphite $229 free ship no tax:
Radian RXT Sun Burst $229 FS, no tax:
The R100 is also $169.90:
While these may not appear to be super slick, for me (in Washington State) this is a great price (due to Amazon tax). CCC says the lowest price on amazon was $219.99 back in 2013, I bought it from Amazon 2 years ago for $200 (amazon price was $250 but there was a $50 off diono coupon). I ended up returning the carseat due to weight and went with the Britax Boulevard click tight...which is my favorite carseat. I need to buy two of these RXT's due to a third baby and needing to fit 3 across the back seat of a sedan.
The savings on tax and free shipping make this almost as good of a deal as I've ever seen. Hope this helps someone else out.