I've never been particularly interested in rules for game masters. Guidelines are awesome, but rules are restrictive. The guidelines for putting together encounters are particularly good in 4th edition, but advancement due to experience has always been an aspect of D&D that I hated as a GM. If you follow the rules as written they are mathematical handcuffs on an aspect of the game that's really important. Reaching a new level is an important reward that evolves the way a PC plays the game, opening new options and keeping the experience fresh and exciting.
I'm currently using an alternate advancement rule. Characters advance in level when I say they advance. Pretty simple, no?
My recommended GM's guideline for when to give PC's a new level is "Advance your characters when you believe it will lead to the most fun." For me, there's a certain amount of fun that is discovering a character through playing him. There's the intrinsic fun of building a character by gaining power as they follow the campaign. There's the enjoyment of choosing that power that you've been looking forward to. There's also fun to be had in trying out that power of feat, seeing how it interacts with the other party members, or how it works against monsters or maybe how it doesn't work. When the shine is beginning to wear off and the players feel that they have a good grip on their new set of powers and abilities and are looking forward to their next level, that's when they should be advanced.
Usually, I'll have a quick discussion about how things are going at the end of a session and if the time seems right, I'll say, you're all now level N+1.
It's dead easy and it works. No arithmetic required!
I've found that a level every two sessions (about seven or eight hours of play) seems to be about right for the current game and if we're not having 10 encounters per level in these two sessions, it's really not a big deal.
I do use the XP values marked in monster stat-blocks. I use them as a guideline to balance encounters, because for that purpose XP works very well. For leveling, the informal approach works better for us.