1.)What is this bow made of? I can't seem to find any info.
It could be Maple, Red Elm, or some sort of actionwood as typically most production bows use woods that tend to be consistent and predictable. It almost certainly has fiberglass backing as well as on the belly of the limbs. Some of the more exotic woods available from custom bowyers require special handling and preparation in using them to make a bow. That is also why most production bow companies shy away from offering them. That is why the wood chosen for your production bow is most likely a standard limb wood like Maple or Red Elm.
2.)What is the practical difference between this bow and more expensive custom bows?
With a custom bowyer, you can have your bow made to your drawlength, which will allow the bow to perform at it's zenith when drawn and shot. Also, if you have a long drawlength, you can benefit from having the overall length of the bow increased, because the length of a bow is determined by the draw length of the user.
If you happen to have exactly a 28 inch draw, you won't gain near as much in performance aspects from a custom bow, as someone who draws 26 inches, or someone who draws 30. (note: most production bows are tillered to be drawn 28 inches) For the short draw shooter, a custom bow will offer increased performance over the production bow they are short drawing. For a long draw shooter, it will allow a bow that will be comfortable to draw to 30 inches with no stack, as well as increased performance over a bow that is tillered to draw 28 inches but is being overdrawn to 30.
Also, with a custom bow, you can have the grip made to fit your hand exactly, as well as have it tillered for split fingered shooting, or three fingers under.
As far as cosmetics go, the custom bow can be ordered in lot's of different wood combinations, with custom scrimshaw and overlay work, as well as special limb core materials that offer extra performance like bamboo and carbon.
As far as performance goes, to be honest there's not a lot of difference between a custom and production bow. Some folks will say that 20 or 30 feet per second of speed is a big difference, but in my opinion it isn't so. What is important is arrow tuning, not arrow speed. Usually when someone is excited about a bows performance, it is a matter of 10 to 20 feet per second that they are fascinated by. Basically, most bows shooting less than 160 feet per second are slow and any stickbow shooting over 190-200 is smokin!
In my opinion, custom bows are good for someone who has been shooting long enough to know what they can really benefit from in a custom bow. Otherwise, it could be a lot of wasted money for a person new to the sport.