[QUOTE=Saltine;131390]An anchor system is definitely the cheaper route from a build and operational standpoint. Sure, you have to spend money to move it, set anchors, etc… but a DP rig has to be towed too as far as I know.[/QUOTE]
That is not entirely true about being cheaper. I can think of other pros and cons, but at the end of the day they are probably about the same to operate. The DP rigs may be a little cheaper even. You start dealing with rental equipment, anchors, synthetic rope, chain, suction piles, the huge boats required to operate in deep water, ROV crews, anchor handling companies and engineering required to set out a rig in 10,000 foot of water then DP is probably cheaper. You operate in 1500-4000 feet of water then maybe moored rigs. I have worked only on DP semis, but I have set out many anchored semis from an anchor handling vessel. To me DP is the winner hands down.
I navigated this rig from Singapore to Mexico without a tug.