This season was so-so...
I own all 3 DVD sets of this show. It's my favorite. However, the production effort of season 4 has noticeably declined. There are still some strong, funny moments, but they're fewer and farther between than in the 3rd season, and there isn't much in there to fill some gaps (Less music, maybe?). Comedic timing seems to be off a bit, camera angles less interesting, and makep makes everyone look too pale most of the time. The lack of Brad and Denise is very apparent, although the new people are interesting, but not particularly funny.
There's still some magic left, but it's obvious they're spending less on the show to produce, leaving me, the die-hard BL fan to long for the good old days.....Buy it if you're still hooked, but I'd start with an earlier season if you've never seen the show.

Great humor.
I have watched every episode of this series. I love the subtle humor. If you liked Alley McBeal or even Night Court, try this series.

All Rise for the Honourable 4th Season
In my opinion this is one of the best seasons of Boston Legal. I am really disappointed however that the fifth will apparently be it's last.
Shatner continues to deliver a top notch character. One of the highlights of the season and in my opinion the best episode when Denny and Alan go before the Supreme Court, what an excellent episode!!
I am really looking forward to season 5 and rewatching the whole season from the start.