Blitzcrank is one of the most annoying champions to play against in League of Legends, but also one of the hardest to play effectively and master. If a Blitzcrank cannot land a pull then he is as useless to the team as an single minion. He also has a very specific build style that only can be compared to the new Ryze. The mantra mana, mana, and more mana. If a Blitzcrank can land pulls and farm enough gold to feed his mana addiction he can be one tough nut to crack. His info can be found at http://www.leagueoflegends.com/champions/53/blitzcrank_the_great_steam_golem .
This ability is in theory one of the best in the game allowing Blizcrank to pull his opponents to him, which can be dangerous under a turret especially, however there are many flaws to this ability. The first one is its a skill shot that can hit minions. The second flaw is that it has a built in delay in between when the ability is clicked to go and it actually releases. This makes it very easy to dodge. That and the fact that ranged champions can stay out of its reach most of the time. Positioning and timing are way to crucial for this ability.
This ability is a great attack speed and movement speed buff, sadly it does not work well on Blitzcrank. He does not require or use attack speed very much, and the only real use for the ability is the move speed. This move screams RUN AWAY!!!
A critical strike with a short pop-up. It is a nice disable, however it has a long cool-down early game and is countered by blinds. Also, it can be very buggy because of how it resets the attack animation on Blitzcrank which can give the target time to flash away.
It is a nice short AOE disruption and a decent damage nuke when cast, however the passive effect is more of a annoyance than anything else. The random nature passive effect means it disrupts last hitting during the lane phase, and can hit a champion under a turret drawing tower agro which is most annoying. Sadly other than using the active there is no way to toggle off the passive.
A very nice tank ability. Allows the champion to take a lot of extra punishment. Can be used to help bait opponents into traps when Blitzcrank is low health. Sadly, it cannot be manually activated so it is no use against harassment and the cool-down is long enough that it cannot be used repeatedly in battle.
Blitzcrank is very versatile, he can be a mage, tank, or a DPS. This can be useful when it is unknown what roles need to be filled on a team.
Because of turret and grass positioning, the best lanes for him to be in are the bottom lane on blue team and the top lane on the purple team.
The threat of his pull and pop-up combo allows him to solo lanes easily while last hitting. This also keeps other champions off his turret and forces them to play more cautiously.
Blitzcrank himself is not the greatest of champions, that said however if one becomes good at this champion he can change the outcome of games especially early game, or can force the other team to play a lot more safely. It is the threat of what Blitzcrank can do, and not the champion himself that causes him to be a valuable asset to a team.