I find the plastic tanks to be interesting, straight bolt in replacement with a protection plate if required.
Are you all in favor of steel tanks because that's what you are used to, or do you have some good reasoning behind wanting steel?
Plastic is light weight, doesn't rust, bends rather than splits or punctures, vs steel.
I'm not sold either way I just like to keep my options open.
Here are some of the criteria I used to buy my TF tanks:
I can fix a leaking steel tank in the field (soap, tire patch, RTV silicone, or liquid steel). I can't fix a leaking plastic tank, the flexing will defeat the soap, patch and RTV, and the RTV and liquid steel won't stick well to the plastic.
The TF replacement tanks are bolt in also, no advantage either way. However, TF does offer 'factory' installations, they did both of mine for the price of 1 ($100, it was on special) and an afternoons wait. Titan doesn't seem to offer 'factory' installs.
They are also somewhat (25% or so) less expensive ($800 vs. $1069), especially since the skid plate from Titan is also plastic, and another $100. Titan charges a flat rate shipping which is disadvantageous to people who are nearby, TF charges actual costs.
TF has tanks available for gas, as well as diesel; replacement and crossbed tanks, Titan is diesel, replacement, only. Shipping weight on the TF 60 gallon tank is a bit under 200 lbs, I have no idea what the weight (shipping or actual) is on the Titan, but one of the (minor) reasons I have the bigger tanks (especially the cross bed) is to get some weight in the truck for daily driving, to smooth out the ride a bit so the extra weight isn't exactly unwelcome.
However, Titan does have a replacement tank that is somewhat larger - 67 gal vs. 60, for an additional $200. This one offers a steel bull-nose protector on the front: I wonder if they discovered they needed more protection?