I've had a Hilux professionally treated, and in all honesty without blowing my own trumpet i've done at least as good and possibly better jobs since of treating 2 owned Landcruisers and one Outback, am almost finished re-treating my present LC and have already applied the initial hard paint coating to the good lady's Forester suspension/subframes, with full wax coating and cavity injections to follow once its been LPG converted, in two week's time.

The main benefit of DIY is obviously a large cost saving, it takes roughly £250 in product (i use BIlt Hamber mainly due to the ease of use and their superb cavity probes as well as quality) to do a thorough job of a LWB Landcruiser to give you an idea, that's around half the price the pros charge.

Most important before you start any treatment is to get the underside clean, and that includes jetting the whole of the inside channels of the ladder chassis through because an awful lot of salty crud will be inside, some people seem to think driving on wet roads is enough to wash that salt residue off :-) nope, so you'll need access to a high water flow rate pressure washer and preferably a 90' wide spray pattern lance to help get in the nooks and crannies.

I can go into more details if you are thinking of DIYing.

There probably isn't a much to choose between BH and Dinitrol for product quality, but for DIY ease BH have it for me.