The Siberian Cat is a natural breed of semi long hair domestic cat. Natural breed means that they developed in a specific geographic area which lent itself to the development of traits which would help them survive. In this case, that geographic area was Russia although at the time it was the USSR. The Siberian Cat develop a thick triple layer coat for protection in cold winters with a slightly coarse texture so that it would be all weather and not prone to matting. Their ears were rounded so that they wouldn't suffer the frost bite large tall ears might be likely to have with lots of ear furnishing and often lynx tipping to provide protection. Their bodies were heavy set and stocky with a brush like tail to wrap around for warmth.
The Siberian Cats temperament is often referred to as Dog like. This is definitely true. However, keep in mind that every cat is unique in their personality and experiences and the broad attribute of dog like temperament may or may not be exactly spot on.
When deciding if a Siberian Cat is right for your family there are some things to consider. First, while they are a moderately large semi-longhair breed they are more active than some of the others. They are also very inquisitive and known to get into mischief. If you are looking for a cat to just have lying around the house to just pay attention to on weekends, you probably are not looking at the right cat. The Siberian needs interaction and stimulation especially as a kitten or they will make their own adventures - and not ones you want them to. If you tend to work during the day or are busy, I'd recommend getting 2 so they can keep each other entertained. Of course you should e prepared to give them lots of attention anyway but this will keep them busy.
Animal Planet aired a nice program on their Cats 101 show, but it did contain some errors. The Siberian very rarely reaches or exceeds 20 lbs. Average for males is 12-18 lbs. Yes, that's a broad range but it reflects the natural breed and real variations. Females are most often from 7-12 lbs. You will see those both smaller than or larger than these ranges but that is the most often seen.