Pros:
Shen has good poke, lane sustain, and utility for withstanding damage as well as initiating and escaping fights.
His Q and Passive help when farming and makes up for not having waveclear.
Shen can do alot of damage over-time based on a percentage of shen's health giving shen a little more damage from bulding defensive items.

Cons:
Shen has small or average base values and scaling on his non-ultimate abilities, so he cannot burst down his opponent.
Shen will fall as off in lane at lvl 6 because most likely he will be pitted against a champion with a damage ability ultimate whereas his ultimate does nothing for him in lane and using it wll cause shen to sacrifice his tower if he does not have the teleport ability to get back to his lane.

ARE YOU FAMILIAR WITH THE TAUNT/FLASH?

An effective way to maximize the number of people you taunt or simply to increase the range of your taunt, use it in sequence with the summoner spell flash. This combination can pull offsome mind blowing plays, just flash into position and taunt as many ppl as possible or taunt then quickly flash to enemy location before shen can complete the full taunt, leaving them no time to counter or escape. (The taunt flash as opposed to the flash taunt is very difficult to pull of and requires some practice before attempting in games.)