I am getting upset with this post. Tell me if this has already been said, but if anybody saw the cartoon you would have seen Grievous fight 5 Jedi, while using only two lightsabers, (and win). The clones then arrive to help the Jedi and fire every weapon they have (even a gunship shoots at Grievous) and he still avoids every shot. The clones are forced to flee with the three injured Jedi (the other two died), and they detonate about a dozen bombs the kill the droids. Unfortunately, for the them Grievous survived the blasts, and defeats two other Jedi another chapter (plus he can use 4 lightsabers).
This is a toughy... If you really look at it Grievous has killed Daakman Barrek, Sha'a Gi, Tarr Seirr, T'chooka D'oon, Soon Bayts, Adi Gallia, Roron Corobb, Foul Moudama, Puroth, Mystammall, and Jmmaar. All which were Jedi so he does have SOME good tactics you would imagine, Boba pulls something amazing off and wins though.
Grievous is a tactical genius with vast strength and hyper-kinetic reflexes and he was trained in lightsabre combat by Dooku himself. Even if Fett uses his jet pack, Grievous wil dodge his fire, leap after him and slice him up a treat. Plus Grievous can use ranged weapons too. His cybernetic enhancements probably make him a much better shot.
Grievous has killed hundreds of Jedi. Boba Fett is no Jedi.