At first I was very upset with the Voice work, but then as I started to have him along for more missions and got to hear more banter with him I cannot imagine anyone else doing the voice work.
He murders the comedy and sarcasm, but I also feel it when he is more serious.
The chemistry in the dialogue between him and Sera is great.
On his appearance alone they could have gone a much different route and made him a gruff and blunt hard ass that doesn't take crap from anyone. Yet with Freddie they took the character in the opposite direction making him feel like one of the most trustworthy companions you have.
He will never lie to you or hold back his opinion and at the same time he will give you advice and encouragement when you seek it.
Freddie's voice fits that perfectly in my opinion.