One thing to remember is no one machine will just signal on the good stuff and ignore all the junk. Every major brands has great options, but you won't be a perfect fit with all brands or machines. Talk to dedicated dealers...not some hobby shop with a few machines in a display case. Personally I do 90% of my hunting with an audio only machine and 10% with a display/indicator machine. Other people wouldn't be caught dead with an audio only machine. If it's at all possible visit a dedicated dealer or two...they will have machines you can actually try in a test garden and they'll have years of metal detecting experience and enough great finds on display to make your mouth water.
My local hobby lobby actually has machines to rent. (For people who lost something and want to try to find it themselves.) So that's one way to try at least one or two machines before putting down your money.
There are a couple of great dealers who work with this site. Talk to them to help narrow down your options.