I thought it was just OK, at least when compared to BoB.
While the combat scenes were pretty well done, it didn't seem like much time was devoted to developing the characters, even the three main ones. BoB did this
very well in comparison while retaining top-notch realism. In TP, I never felt very engaged by any of the characters. I thought the actor who played Snafu stole the show.
I think they would have done better if they had left out the Basilone story. I'm not saying it's not a story worth telling, but I think his exploits and life would be better served as it's own movie. However, there was virtually no crossover with the other characters other than he and Leckie both being on Guadalcanal. The time saved could have done wonders for fleshing out the rest of the stories (3 months of Okinawa in one episode??)
Another thing that really bugged me was that it wasn't 10 60 minute episodes as advertised. They all ended around the 54 minute mark and that isn't even accounting for the annoying 3 minutes of credits at the start of each one. I'm sure the DVD set with bonus material will exceed 10 hours, but actual run time is closer to 8 1/2 hours.
Overall, I liked it and watched every episode with my 9 year old boy. Based on things he's said about it, he really learned a lot from it.