The 6000 DI Pro SL is a powerful detector that is best suited to coin, relic and treasure hunting. It does not like wet salt sand although it does have a TR disc mode that will Disc out salt beach sand but depth in those conditions will not be as good as a good beach dedicated machine like The Excal, BHID, SOV series, and beach PI units. It sounds like a multi frequency VLF machine like the SOV or Excal might suit you as a general purpose detector.
If you tried a beach dedicated PI you would not be happy with its performance in iron mineralised ground away from the beach whereas the Sov and the Excal will operate anywhere except in high iron mineralisation and even there they will be better than most other single frequency VLFs.
If you tried a PI such as the Infinium that will work very well in any ground and is waterproof you would have to contend with digging a lot of trash due to the lack of good discrimination and if you intend to do the parks and show grounds then this machine might be a bit of a hand full for a beginner.
I have found my old Sov XS to be a great general purpose detector and have used it very successfully in the gold fields, Parks, Gardens Showgrounds, Ghost Towns and it is one of, if not the best, salt beach detector ever made. The Excal is a waterproof SOV.
This is just my opinion and I am sure other detectorists have other good suggestions.
Cheers,
Fisher G