Hell's bells - Forester can't hold a candle to O'Brian when it comes to language. He writes a rattling good yard, but in terms of complexity, richness and overall satisfaction, his books are mere potboilers compared to the Aubrey-Maturin canon. A burger and fries compared to a gourmet meal, if you like.
And Jed, you're doing a disservice to your compatriots - O'Brian is probably more popular in the USA than in the UK. In fact, one of the reasons that he caught on over here was because you Americans had rightly spotted his genius when we had snootily dismissed him as "yet another swashbuckling historical hack". For which I thank you!