That is a really good question Carl, and in my opinion ease of use and versatility are the keys to choosing a metal detector.
Those two things make a winning combination on any metal detector, and especially for a beach hunter.
A metal detector may be known for being very deep or it may have a lot of bells and whistles, but if it just feels awkward using it you are not going to stay out on the beach very long.
When you are comfortable using a metal detector, you find stuff and you like it even more. The same applies to using a metal detector that is too site specific. The more things you can do with your detector, the more places you can search and the more good finds you will recover.
In my opinion, the best thing you can do before buying a metal detector is visit your local metal detector store. At your local metal detector dealer, you can pick up various metal detectors and get a feel for them. Probably get a demo and chat with a person who knows the local beaches you intend to search.
Everyone has their favorite metal detectors, but I do like to try new ones out just to see if they are better than what I use.
I need waterproof metal detectors for water hunting, but on the beach I have no qualms about putting a plastic bag over a metal detector if I think it will be a better option than my waterproof units
There is nothing worse than a beach or water hunter using a metal detector they are not comfortable using, just because it is a popular metal detector and people find stuff with it.
There are no one size fits all metal detectors, otherwise everyone would be using the same type of metal detector.
What is a good fit for you and the sites you search, are always the perfect reasons to fork over your hard earned money for a metal detector.