I used my username as the seed and got a pretty nice world. There are a LOT of mountains, and DEEP caves. A lof of the caves open at ground level and just go almost straight down. There was also a few areas of mostly flat land. It's almost like you get a little bit of everything here XD I also found a mob spawner right beneath the surface. I found a tunnel next to a pumpkin patch that opened right next to the mob spawner and chests.
Here are some screenshots I got.
Here is where I spawned at.
Head towards the mountain shown and you pretty much find the rest from there.
Here's the pumpkin patch I mentioned with a screenshot showing the coordinates. It's straight east from the spawn coordinates and was pretty much the furthest point I went to so far.
Natural lava pool past the pumpkin patch
If you're facing the pumpkin patch and turn around, this is what's on the other side.