Forrest has a good defensive guard when the fight starts. The trouble with Forrest is that he no longer has a good defensive guard when he is hurt. Rashad and Jardine rocked him early and finished him in the guard, but when Page or Shogun got him on his back he was very good at avoiding punishment.
Gotta say I'm reluctant to give Forrest TOO much credit (obviously he deserves some) for tooling Shogun on the ground in their fight when most of Forrest's best ground work (offensively anyway) came in the 3rd when Shogun gassed. With regards to Machida, I feel technically he is better than Forrest. I agree with you that he seems to rush on the ground which I suppose can be a problem and where he seems to make mistakes (prime example being the Ortiz fight). But also I think he does a lot of things well. I think his top control is good, he can maintain position, look for a more dominant one and looks for submissions frequently. Another thing that I noticed was his ability to sweep fighters, which he displayed against Sokoudjou and also an ability that you don't seem to see too often.
Machida impresses me more with his defensive grappling and judo skills than his actual submission skills. I do think he's a very efficient ground n pounder though. I think he'd beat Forrest silly, standing or on the ground.
You watched him outmuscle a surprised Tito You saw how he threw Thiago to the ground like he was a lightweight. You saw how he swatted Rashad like he was a little boy. Add to it that hes a master tactician and has been hit 5 times in the Octagon. Id say id favor him a little.
If Shogun Rua`s stamina is sorted (he certainly looked fine vs Chuck even tho it was just one rd) then I think Machida is in for a beating, he`s not used to being pushed to the limit, he likely will handle being pushed, he looks a quality fighter with a warriors spirit but Rua has been to the well & back & prevailed many many times (experience) & is more talented than any fighter Machida has ever fought... this will be a real eye opener between the top 2 LHWTs in the world, cant wait. I`ll be betting on Shogun Rua.