Have fished Cabo several times since 1997, usually in early Jan & as late as March. Always different but always great fiHishing. The striped marlin are always around and casting livies to 'tailers' makes for really exciting visual fishing. We always take our own gear & fish 30lb class gear with Shimano TLD25/30's for casting & 30-50lb class gear for trolling. We do this as the gear on the local boats can be a bit over-gunned. There is always the chance of a blue turning up but unlikely at this time of year. Apart from the marlin, the tuna fishing should be really starting to fire & you can get some real good ones among the 'footballs'. Friends have had fish to over 200lbs. The mahi-mahi should be around in numbers & of course the 'rooster fish' - fantastic fun on lighter gear, although again, 50lb fish are fairly common.
As far as boats are concerned, as Beach Boy said, the Pisces Fleet are a good operation, although we now always fish with Efren Beron on Guerita. I think Efren was probably born with a fishing rod in his hand. He just has that certain something & always seems to come up with the goods for us. Efren won the release division of the 'Bibees Black & Blue Marlin Tournament' a couple of years ago fishing with a group of friends of mine, netting them about $100,000! The boat is a little scruffy looking but it certainly attracts the fish!!!
Guerita's standard rate is $600 a day but if you're fishing a few days he & his American wife Jaquie are negotiable on that - $500ish plus bait & tip - feel free to mention my name.
His website is www.gueritasportfishing.com
& The Pisces Fleet is www.piscessportfishing.com
If you fancy having a go for a 'rooster' or 'sierra' you're probably better off hiring a 'panga' for about $30 an hour (again negotiable depending on the type of panga). If the 'stripies' are close in and the sea is flat, it's great fun catching a marlin on one of these. A good panga used to be 'Bluefin II' but I don't have any contact details - you'd have to wander around the docks after the boats come in (about 2pm).
Anyway, hope that helps a bit and you get a heap of fish (make sure you let all those beautiful marlin go though).