I loved all three.
Yes, the acting was piss-poor in places (Anakin) and great in others, in my opinion (Qui-Gon, Obi-Wan, The Emporer and Count Dooku).
Jar-Jar I am very indifferent about.
I found him amusing as a child, and tolerable as a teenager.
But, as OP said, the spectacle totally makes up for any faults.
The granduer of the battle of Geonisis, the eradication of the Jedi, the Naboo saber battle, and pretty much every epic battle was absolutely stunning.
When each and every Jedi is betrayed at the drop of an order, though.. Still brings a tear to my eye.
General Grievous though, man, the FUCK?! They bigged him all up in the Clone Wars cartoons, and then gets killed by Obi-Wan, which would be acceptable if he had actually put up a good fight. Obi's just like "*****, please." as he cuts off two of his hands in the first 20 seconds.