In terms of "believability", all religions... at their very core... are equal in my opinion in regards to whether or not there is any concrete evidence to support their individual beliefs/dogmas/laws etc. (none, imo)
The main, modern religions of today have all "borrowed", to one extent or the other, bits and pieces from those religions that have come before them (and in the process, claiming them as their own). The resulting "cross-pollination" of beliefs, rituals and historical accounts... along with the myriad of sub-faiths based on differing interpretations overs these issues... makes it difficult at best to muddle through which one has "the upper hand" in terms of credibility.
In regards to which religion I would find more respectable if I were to believe in a god... it would be whichever faith had taught that after the creator had set the cosmos in motion, he sat back and allowed humanity (and any other lifeforms out there) to get on with living without ever once mucking about with their lives: no miracles... no saviors... no picking and chosing who is worth "saving" or not...