Nothing is boring to paint, its just a matter of whether you can find inspiration from the models and create something cool over it. The plain blue and white scheme is a little dull, but remember you can paint any army however you want. My High Elves have a deep red and bronze Spartan theme, including the lambda (upside V) on every shield, banner and some cloaks. They look cool and are great fun on the battlefield.
The entire purpose of PG is to be really hard to kill. Also, they cause fear which is a nice bonus. They are a good way to deliver your general to the fight. 18 PG 6x3 now puts out 13 s4 attacks, rerolling any misses and striking first. Not bad. Now add 3 s6 attacks (great weapon noble) also striking first and rerolling misses and you have a formidable unit that is very hard to kill. Plus the models for them are absolutely amazing, that is the main reason I use them. And I'm not talking about the new bulky plastic crap, I'm talking about the quality metal PG who are IMO some of the best models GW has made.
White Lions have a different role; they can be hard to shoot with their lion cloaks, the stubborn makes them stick around in battle even when flanked, and they dish out impressive s6 attacks. They are easier to kill in combat though, and obviously no one wnats to be near them so they take a lot of shooting and baiting. I'm a big fan of the lion chariot; that thing also causes fear and deals a very impressive 4 s5 attacks and 2 s6 attacks (the latter two rerolling misses and striking first) and that is before considering impact hits!