They are not the warmest, they have rather thin liners
they are not the cheapest, buy some kincos and whatever waterproofing wax flylow uses.
They are not the most waterproof, you are going to look for goretex or something for that.
BUT THEY ARE STILL ONE OF THE BEST MITTS AROUND!
There are days that my fingers will get cold even with liners. Usually it is around -10F and I will forget to warm them up on the car heater before I put them on (this is the key to keeping you digits warm with any pairs of gloves). I only have a pair of very thin next-to-skin liners so having a pair of thicker liners is a must for when it is very, very cold. The insulation is pretty thin, so they keep quite a bit of dexterity, especially for mittens.
You could definitely buy a pair of kincos for 20 dollars less and wax them yourself, and co through that all yourself, but i chose flylow because they are a Colorado brand and it just seemed like the easier route. I have felt my friends kincos and the leather isn't as flexible and it is pretty inconsistent in thickness.
They are definately not the most waterproof. You could spend a LOT of money on getting the most waterproof gloves. But they get the job done and at a point, having the extra waterproofing of a nicer glove seems unnecessary. The only time they get wet is when I am deliberately dragging them through wet, thick snow.
TLDR: buy the Flylow Oven mitts...
and the Ridge gloves and the Tough Guy gloves for the price of one pair of Hestras.