I played a bit of 1.9pre4 and I quite liked the round sun. I think the square moon looked better, though.
In pre4 I played around with enchantments and ender pearls before using eyes of ender to locate a stronghold. I then entered The End. The End is fucking freaky. It's hard to fight the endermen without aggravating more. Eventually you will get mobbed to death unless you're a cheater like me and use golden apples, strength potions and enchanted diamond equipment. I decided I'd try fighting with nothing more that an iron sword once I tired of enderman slaying and was promptly killed.
Also, this was what the stronghold I found looked like.
Fighting Cave Spiders and Silverfish at the same time is not fun.