Trip to the basement in the A.M. - discovered water where there ought not to be any. Bottom of old tank had cracked open and water was gushing out. Spent about an hour trying phone numbers on tank - all dated info. Noticed Union Energy number on furnace, called it and were redirected to Reliance.
Person answering was friendly, knowledgable and most important, reassuring. She walked me through ensuring everything - including the gas - was shot off correctly. She then transferred me to sales, where we had a new (rental) heater lined up for 4pm-8pm THE SAME DAY. Arrived at closer to 5PM, but had called to let us know he was on his way.
The install took longer than it ought to have because it turns out Joe is an iPhone officianado, too, so too much time spent chatting. HOWever, it was done quickly and very well, and included explanations of everything from top-to-bottom, including what he was doing, why he needed to do it and how the new heaster functioned.
Now only are we pleased with our water heater, we are going to get both a new furnace and new A/C the same way. Purchasing is probably cheaper in the long run, but renting provides the sort of insurance & assurance we didn't have with our old, owned tank.