Each dog is different, but you should never count out a male. If it were up to me and I was not breeding I would have all males. People often want females because they are "more laid back" than males. I have to say that is totally untrue. Most of the time my males are more easy going than my girls. Females are usually the leaders of the pack. They tend to be more bossy than the males and more independent. I have also noticed that my females are very territorial of areas they think of as theirs. None of my males stake claim on a certain area of the bed or a favorite toy like my females do. Also I have seen a couple of females that will also mark their territory by peeing in the house just like the males get blamed for.
Females can also be horribly moody, going from happy to ornery in just a flash of seconds. Usually if a fight breaks out it is between 2 of my females and never my males. Remember there is a reason they call girls "bitches" LOL. Also on top of all that you have the cycles of the female to deal with if not spayed. This can be very messy and time consuming as you have to guard your female extra carefully during this time if you are not breeding them. Also in most cases you can plan on spending more on a female because of their breeding capabilities.
Males on the other hand are very loyal and protective and bond very well to you. They are less territorial than females are and can adapt much more quickly than a female to new situations. If a male is neutered early or trained carefully they will not lift their legs. This seems to be the most common complaint I hear about males. I have several males and I have had them all together in the house. None of them lifted their legs to mark on anything in the house because we trained them not to. It is not as hard as people make it out to be.
Now outside is another matter as full intact males will mark their territory. But goodness sakes it is "outside" after all. As far as a difference between males and females when it comes to activity level I have seen that some females want more play and exercise than their male counterparts but there isn't a whole lot of difference. I will say that in poodles in my opinion I have found the miniature poodles to be most active of the three varieties. Some poodles are couch potatoes and some live to get up and go. This is something that should be matched to the family the puppy is going to more than a decision that is based on sex.
Sometimes it does not matter what a breeder says, people are just stuck on females. But you really should take into consideration what your breeder is telling you would be the better pet for you..