I have read dozens of first hand accounts, war diaries, memoirs from Tiger crews and one thing is perfectly clear. The Tiger could be driven into combat, take punishing hits from enemy guns and dish out a lethal reply. It was an offensive weapon to be placed right at the front of the Schwerpunkt. Kursk represents the best example of the Tiger being used the way it was intended. On the defensive it was held in reserve and sent to counterattack enemy breakthroughs. To portray it as some sort of lumbering giant only useful in the ambush role isn't accurate. As for reliability it compared quite well with other German tank models. The German recovery and maintenance units had an amazing ability to recover, repair and return tanks to combat.
One reoccuring theme that I came across in my reading was the number of Tigers that were scuttled by the crew. I suspect that more Tigers were destroyed by their own crews than enemy fire. The reason for this was usually to prevent stuck, damaged or out of fuel vehicles from falling into enemy hands.
Its biggest deficiency was it's tremendous weight which precluded the use of all but the sturdiest bridges and strained the drive components.