Hi phrunt, I really like the SDC both here and in Aus, I have only used it on the beach here in NZ seems to work well but it is not hunting gold but coins and jewellery. For dry sand I use mostly sensitivity +1 or 2 for wet sand -1 or 2, Aus usually +4 or 5. Swing speed needs to be slow to very slow I find.
The SP01 is awesome both on the SDC as well as the V3i, I got the pro headphones at the same time as the SP01. They seem to work well together.
With the recent purchase of the GPX5000 it came with quite a few accessories, Booster, from memory 5 coils, harness, pick and belt holder and aluminium carry case, covers and push stick. Was an excellent deal I feel.
My friend in Aus took his GPX5000 as well as mine, both with same settings and coil and he said he was very impressed with performance of my new purchase. Sounds pretty good.