We are going to be at Te Anua in early April
and will not have time to do both Which one offers better value.Also has anyone been on the overnighttour of either?

If you enter "doubtful or milford" in the search box, you will get dozens of replies and reports. I think this gets asked every week.

I'm not the official welcomer, but welcome to Fodors anyway.

As mlgb says, if you enter your search words in the box, and indicate New Zealand, you will get much more info than you would get by one post.

Milford is a better monetary value, in that it is arguably more beautiful and boat tours are cheaper, because they don't travel as far. I much prefer Doubtful though, because far fewer people go there - it doesn't feel as busy as Milford can when there are a dozen tour boats in view. Doubtful takes longer to reach and costs more, but I would consider that worthwhile for the more solitary experience.

Going overnight at either Sound is a great idea, because almost all the tours run in the daytime. It is really wonderful to experience both dusk and dawn while floating in one of the Sounds. Again, Milford will be cheaper, but Doubtful more of a wilderness experience.

Since you are going in the near future, you may be limited by availability. I read and read about both sounds on the internet, posted a question just like you can made the post difficult decision--we would do the overnight on Doubtful. I called Real Journeys by phone and learned that on our date, the boat was completely booked--and I called 11 months in advance! I have the feeling that both are a fabulous experience and the boats are the same. Now that we are going on Milford, I am sure we will be delighted. Before you make your decision, check on availability first.