The ToughGuard was updated at the beginning of the year, but have yet to see what the update was besides a price increase (Walmart did a clearance of the "old" ones, and the shelf had TG with "improved" on them (or something to that effect) to hint at a change).
At least with the regular orange cans, we know that they were upgraded to silicone ADV, but the price stayed the same.
I personally feel with the recent price increase of the Toughguard that it is not much of a difference between that and an Ultra, and in a few cases, there is only $0.60 difference in price at Walmart.
When they were in the low $5 range, they were a really good deal, but in the mid $6 (or higher) range, not as good of a deal, but still a really good filter.
I have several of the "old" TG for my truck and motorcycle.