Grimlock has actually been poorly served by toys over the years, the original being the best released (until this one). Interestingly, this toy seems to take it's cues from the old Pretender Classics Grimlock and Derek Yanniger's depiction of the character in the Marvel Generation 2 comic (typically I can't find a picture online, and I can't be arsed to scan a comic).
In Dino mode, Grimlock looks pretty good, the hind legs are extremely poseable, as the forearms which are on little ball joints. The usual features are there: opening and closing mouth and a poseable tail. In this mode, the standard Grimlock colours (gold and grey) are prominent. There is a black wash on the torso, which nicely picks out the fantastic molded detail.
The dino's hind legs become Grimlock's arms in robot mode, giving the toy a powerful look that befits a Dinobot. Although the robot mode features the trademark gold chest, there is a lot of black used - the legs and waist for example, which is more in keeping with Pretender Grimlock than the original toy.
There's no real restriction of movement in this mode, although the legs can be a little cumbersome. As far as weaponry goes, Grimlock has two, both based on Pretender Grimlock. The missile launching gun is clearly based on the aforementioned toy, check out that bayonet! It would have been nice if the designer had put a post on the rear of the gun so that it could be held like a sword. Speaking of swords, Grimlock's tail can be used as a blade, although it's not exactly convincing and is better stored on the toys back.
As with more or less all Classic / Universe 2.0 toys, it's hard to find fault with the toys. Grimlock easily slots into that category and is one of my favourite toys. As one of the Transformers better known, and dare I say it, glamarouse characters it's fitting that he was one of the initial Classics line. There's only one band I could possibly compare Grimlock to: T-Rex.