Personally I prefer using a single frequency VLF in the more troublesome areas like old house sites with abundant rusted iron disseminated throughout the soil, with FBS based detectors more suited to finding deep high conductors in relatively clean ground. Different stokes for different folks really, for every you tube clip showing the shortcomings of these detectors, there are plenty around showing owners having a great deal of success. FBS will not suit everyone, and there are some who prefer to own both a CTX/Etrac and a Deus for the areas that suit their strengths (Deus being more suited to searching for small/thin low conductors amongst iron).
Also there has been very little talk on coil usage to suit certain sites. To me it is a no brainer to utilise the services of a smaller coil to improve target separation and the response of the detector in junky areas. Less targets under the coil at any one time results in less target information the detector has to process, hence should speed things up to a degree. For this reason I always carry a smaller coil should circumstances dictate the need for one.
If a good deal of beach detecting was a part of my detecting activities, I would definitely choose an FBS or BBS based detector over a VLF any day. No need to ground balance constantly, or set up the detector with a multitude of settings to have it running with any sort of stability. You can go from dry to wet or wet to dry, or even straight into the water with little or no effect to the stability.
Whilst you can get a VLF to work to a degree in such situations, ultimately it will result in compromised performance on order to get it running satisfactorily. There is a good reason why most seasoned beach/water hunters prefer FBS in such scenarios, have a look over various forums and that will soon be apparent.
Ultimately both have their limitations and advantages under certain scenarios, there is no escaping that. You just have to weigh up where a majority of your detecting will occur, what features you are looking for, and what suits your budget. There's no denying that both detectors have produced a hefty amount of finds over the years to prove their worth, so I don't believe in canning either for their shortcomings - operator experience certainly plays a huge part in how successful one is.
Either way, I'd be happy with one or the other, or both in my inventory - as they say, variety is the spice of life.