A New Man is a great episode; it's not brilliant but it's a good laugh and gives Giles (underused this season) something to do besides sit around all day! It's a big step up from the previous episode and is a fun ride.
Giles doesn't have much do in Season 4. Sometimes it even felt like the writers were struggling to find ways to include him and I think it's a shame, as he's a great character. He's very funny here and the whole turning into a demon thing was a good idea. I really hated Maggie Walsh for looking down on him and acting as if she's better- made me laugh when he chased her down the streets of Sunnydale. I really don't like her.
I'm sad this is Ethan Rayne's last episode; I think he's a very interesting character, funny and also brings out Giles' dark side. I always wanted more of Giles' history (please give us the Ripper spinoff!) and am disappointed this is his last episode. I loved the Spike and Giles interaction here; they're so amusing together and the car scenes are priceless! Spike is hilarious anyway but his scenes with Giles take the cake. I would have liked more of them but silly writers decide on more Buffy/Wood... eh sorry I mean Riley scenes. Buffy/Riley scenes really don't do it for me. They have zero chemistry together and it's just all so meh. I couldn't care less about their drama and I find the entire thing to be just annoying. It was good for Buffy to have a rebound guy after her first love with Angel though so she can finally move on and meet her perfect match in Spike (:P). I enjoyed the Willow/Tara scenes. I'm a big fan on them two so I love seeing them progress. I feel Willow and Tara are the closest thing to true love in the verse so it's just nice to see them in their early stages.
A New Man is a great episode that is fun and entertaining but ultimately a bit forgettable. It's worth a few watches though and is definitely enjoyable!