Over on the LA Times Blog called Pardon Our Dust, they have posted an entry on how long it takes to get hot water to your faucet with a tankless heater vs. a conventional heater. 

The basis of the story is that tankless owners, myself included, are always asked (told) that we are waiting longer for our hot water.  The author of this blog goes on to prove that the the difference is indeed negligible.  It is nice to see this sentiment in writing after he did some informal testing and I can say from my own experience that he is right.  The difference in negligible.

In my home we do notice that the faucets furthest from the heater do take longer to get a hot flow, but it isn't that much longer than it was prior to the tankless system.  Another problem is that our plumbing is over 60 years old and because of mineral build up we have low pressure trough the hot water pipes anyway.  I think we would have almost no problem if we had new pipes. 

So check out the story here.  It's a good quick read.