First of all a disciplined lifestyle has nothing to do with living a life in excess or not. That is a misconception. Compared to many people in the world you and I are living a life in excess. Are you not leading a disciplined life? Or at least trying your best to do so?
Second of all the Buddha experienced both excess and severe deprivation before his enlightenment. Just saying to fill in the picture.

.
Third of all the Buddha lived 500 years before the Christ and did not have a concept of what *you * mean by sin at all.
But that being said what I am saying is that you cannot judge one system from the definitions of another.
Jesus assisted fisherman in their task of fishing and obviously killed thousands of beings in that single act. That wasn’t very ***skillfull *** at all by Buddhist standards.
See my point?
I am not familiar with the life of Jesus but if I was I am pretty sure I could point out many more things that are skillfully questionable. (That is questionable from a Buddhist definition of what is sin)
If not I can certainly pick out loads of acts of the God (your God) from the old testament that are a tiny bit questionable skillfully speaking too say the least.
/Victor
perhaps it would be better to define forms of Buddhism since many Buddhists eat and kill fish (and many Christians are vegetarian) as well as define the word “sin” which means “error”. I’m sure that in the Buddhist pursuit of “Right livelihood”, and all the other “rights” there is an awareness of not hitting your mark or goal and a struggle to do better. That is an awareness of sin. Perhaps the stakes are different due to a belief in reincarnation.
I can see some similarities between Jesus and Buddha in that God created us all and in that design, we do resemble each other. On a spiritual path there are similarities in the human condition. But there are many differences, the first coming from our Christian belief that Jesus was God: "Many men would try to become God or god-like but only One would be God become man.
Buddha came from wealth and power and was protected from suffering for many of his early years until one day he stepped outside the palace and encountered human misery.
Jesus was born in humble surroundings, in a manger, and His parents had to escape with Him into Egypt because King Herod was killing young baby boys, fearful of the rumors about the birth of a Messiah. Jesus was raised by a Jewish carpenter. His parents were of royal lineage but lived in a working class: survival depended on hard work.
Perhaps they both would have agreed that becoming an earthly KING would not be a solution to the world’s problems.
Concerning suffering, Buddha wanted to eliminate suffering and attempted to learn how to shut it out to create enlightenment. He became perfect at that endeavor.
Jesus embraced suffering and reached out to many who were suffering. He healed many. He suffered at the end of His life by dying on the cross in order to free us from our sins/errors and He overcame death by Resurrection. Amongst Christians, suffering can be an offering to God . Jesus was already perfect.
Buddhism is a philosophy in many ways; Buddha is a philosopher. He has been deified by some of his followers.
Of course some branches of Christianity avoid the deification of Christ and reduce Him to a “very spiritual” man (I don’t know many “very spiritual” men who would perform such miracles, and go to their death because they say they are the Son of God, and return again to His followers.
Many truths of Buddhism and ways of living are similar to those truths in Judaism and Christianity, since humans are all on a similar spiritual path of seeking meaning to life.
There is a respect for human life and kindness amongst both. Buddha did come from the Hindu culture of pantheism; Jesus came from a Jewish culture of monotheism.
The concept of how many lives we have and how we achieve “enlightenment” is a difference in that in Christianity, an “unenlightened” person, living only one life, can possibly go straight to heaven through prayer, good actions, and confession. He does not have to achieve “enlightenment”, he does not have to come back again and again to deal with karma.