Only one remaining Spartan II (actually a handful remaining, but other than MC they're scattered all over who knows where. In fact, now MC is who knows where, too).
ONSC, however, has replaced the Spartan II program with the Spartan III program. Now, the first few batches of III's were much more mass-produced, but as established in Halo: Reach some are still given full MJOLNIR armor and for all intents and purposes are just like MC and the other Spartan IIs.
Basically, the Spartan II program was the pre-production test run. The Spartan III program perfected the augmentation process, and is now in full production. Of note is the fact that the augmentation process was improved such that the survival rate went from 44% to 100%, with no detrimental effect on the physiological enhancements.
To note, three full companies of roughly 300 each were raised in a very short period of time. The kids were recruited from orphans, trained and augmented within 4-5 years, if not less, then sent on massive suicide missions. They were basically dropped off on vital covenant planets with no backup, against superior foes and inferior technology, and still were hugely successful in creating massive amounts of damage.
Some of them were withdrawn from the normal companies, and were trained and equipped more as Spartan IIs, with the best possible equipment and trained into adulthood, rather than being sent out on suicide missions at an average age of 11-13 or so.
Most Space Marines Scouts probably haven't even been recruited yet at that age, let alone sent out on suicide missions without any form of support. Based on that fact alone, no SM scout can compare with a Spartan.
I wouldn't be sure of that. There are too many other examples of power-armored super soldiers that are much more mainstream. Spartans are a direct reference to the Spartans of olds, given updated armor, weapons and training.