one of the comments state that this burner is for med-lrg pots, and maybe too big for solo cooksets...is this true? would a snow peak 600 not sit well on this stove?

The worst pot made for efficiency and boiling water is a tall, small diameter titanium pot. Why do manufacturers make them? Because they're small, lightweight and easy to pack. The Snow Peak 600 Pot was designed, first, to accommodate one of their canisters and a stove inside the pot. Efficiency and boil time weren't considered as it's primary functions. Many stoves, such as the MSR PocketRocket, are perfect for these types of pots, like the Snow Peak 600, because they center the flame directly in the middle of the pot. Titanium also has poor heat conductivity so the only water being effected by the heat is on or near the bottom of the pot closest to the flame. The Simmerlite (and WindPro which is very similar) are optimum for 1L pots and larger that have larger circumferences, but shallower profiles. A good example of this type of pot for a solo backpacker is the MSR Quick Solo. It is made from aerospace aluminum that's been hard anodized. But it's the shape that makes the most difference. You will find water will boil much faster with less fuel than the Snow Peak 600 pot. The Snow Peak 600 pot will work with the Simmerlite, but it isn't optimum. I would recommend the canister SnowPeak stoves or the MSR Pocket Rocket. Unfortunately there isn't a liquid fuel (non-canister) stove that will work optimally with this type of pot currently.

Its not so much that it wouldn't sit correctly, but more that the shape of the burner would direct heat around the outside edge of a smaller pot, causing the loss of precious heat/fuel. A stove with a smaller burner (Soto regulator or MSR pocket rocket are just two examples), would direct more of the heat towards the center of the pot.