If no one offers any 'personal experiences' regarding your question, I CAN tell you that a LOT of folks these days are asking about them.
What you could do is use your Browser's FIND (or Search) Feature whereas you type in the word tankless into the 'Search Box'. Keep looking as there are a LOT of Posts on this! You will find Brian 'Tankless' Wood and Harold on the BBS talking about them. Perhaps, here and there, you'll find 'bc' talking about them.