Are texture packs in minecraft PE worth the effort?

Texture packs are too much work sometimes - but in Minecraft PE's case you have to be determined to install any (especially multiple).

Your buildings stay the same, however they might not look the same/as good just due to the change in texture. However they will be the same block 100% just look different.

If you hit 'esc' you'll open up your menu and there should be a texture pack option and all your texture packs will be listed there. Turning them off and on is as simple as a button click.

Some texture packs can make the game run slower just depends on your computer, the server/map, and the texture pack. Higher detailed texture packs can cause lag due to the larger images.(More pixles) I find it safe/best to be 32x32. Its decent on detail and not laggy(However that is my computer)

As for nice texture packs/realistic its all up to you really. I find most people/server run with Conquest. But that's just mostly the servers I run around on. Its a medieval sorta theme with metas and connected textures. However for connected textures and metas you have to have mcpatcher or optifine.
http://www.planetminecraft.com/...est-32x32/

Its only worth the effort if you know what you are doing. If you do, then totally get a texture pack.