Hello jefatk,
Welcome. First, there is no "best" 1st time detector, just a LOT of good options.
When I bought my first detector, I did some research on available features. Two features were a requirement for me:
1) Adjustable ground balance, either manual, auto, or both. This gives you the ability to operate in a variety of mineralization of ground, in your area. Some machines mentioned, have factory preset GB which may limit the machines abilities in changing ground conditions.
2) Good discrimination. The machines ability to discriminate unwanted metals, (iron for example), in very trashy areas. It can make your detecting experience more enjoyable when operating in areas with lots of ferrous objects. It is also good on the flipside of that, to have an all-metal mode for detecting cleaner areas, or relics, which will discriminate nothing. Some machines have a progressive type knob, others have a notch type, where certain areas of conductivity are notched out.
Also pay attention to the type of coil it comes with. Some have concentric, some have DD type. The DD coils work better in mineralized ground and have better coverage.
You can be in a room with ten detectorist's and ask, what the best first detector is, and get ten different answers.
A little research is always best, that way you can choose a machine that fits you. GOOD LUCK