KL tower is a nice tower to get a good view of entire Kuala lumpur city.
There are multiple varieties of tickets - skydeck, observation deck, skybox etc.
I took the ticket to skydeck+skybox. You get a nice view of the city from the top. You can get the side-view of petronas towers from here. You also get to see the majestic Merdeka 118.
There are two skyboxes, one which has petronas towers in the backdrop and another with normal background. You need to spend a considerable amount of time in queue to get to the skyboxes, especially the one with petronas towers in backdrop.
I went only to the normal skybox . I didn't find it worth spending a long time in queue, just to spend 15 seconds in a skybox.