The OO takes some getting used to but once you acclimate its pretty easy to use and saves a suprising amount of work. Especially where templates are concerned.
And as Tom noted the whole site, or page, doesn't have to be OO to make use, even casual use of an OO template system.
I must admit that I struggled to not use OO stuff until I had a better grasp on it. Finally I jumped in with both feet and realized how much I was missing!