Buying detectors can be a real pain sometimes, what one person will suggest, may well turn out to be a hand full to operate for someone else, on the other hand, another suggestion may only work in limited areas, or not have all the required features that you would expect.
On one side of the spectrum, you have people that prefer digital readouts, multiple tones and VDI numbers, whilst on the other hand, some prefer beep and dig detectors with decent discrimination capabilities. I seem to fall in the latter category after trying a few detectors out, I find some detectors are simply an information overload, when all I really need is the capability to listen to a particular signal response, combined with good discrimination to decide whether I dig or not. Part of the reasoning behing this is the fact that I do a lot of night detecting, and I can't be assed to check the screen every time I locate a target. Bit like comparing a Minelab x-terra 705 with all the bells and whistles to say the Tesoro range of detectors with basic ground balancing and discrimination controls
Sometimes it can be a decision made only after trying out a few detectors to find find out what is right for you in the long run. You only have to scour the forum to realise that the variety of detector ownership is greatly varied, with pretty much no machine that fits the bill of a perfect jack of all trades detector, nor perfect all round coin machine. (ctx3030 may come close, and has price to match)
It will also depend on where you want to use the detector. A VLF detector with multiple frequencies would be preferable for dealing with the salty or mineralised conditions (Sovereign, Excalibur, Fisher CZ-3D or CZ-5). I too am looking at doing the same, and the last 4 mentioned detectors are on my shortlist so far, plus will be buying second hand. The requirement for multiple frequencies cuts the list down by a fair bit, those four detectors are affordable for me, whilst detectors like the explorer, e-trac and ctx3030 are still well out of my price, even second hand.
Unfortunately, the Eureka seems to be a bit lacklustre in the goldfields for some reason, with finds few and far between, the Whites GMT and Fisher Goldbug 2 seem to have more success with regular finds. Hence why I have diverted my energy to coin and jewellery detector, with much better prospects of finding something of worth. You really need PI detector these days in the goldfields to increase your chances of more regular finds, plus be able to justify the substantial initial purchase price and the pricey coils to go with them. Overall, for my budget (under $1000), the Minelab Sovereign Elite seems to tick most boxes for an all round, mutliple frequency coin/relic detector. Ask someone else and you will most likely get a different answer based on requirements, previous experiences, and areas likely to be detected in.