Water Heaters - tankless heater system

we are researching to eventually install a tankless water heater but are less than impressed with some responses by local distributors/installers; do we need a detached dedicated circuit for most of these units, or can't the new one just be wired to the circuit in the panelbox that was formerly used for the old water heater? do these units HAVE to be installed in the basement? (can they be placed on the first floor laundry room or in the adjoining garage?)
Lastly, does anyone know of any decent informative websites to find factual info on tankless water heating systems? (not those supplies by manufacturers)

most tankless water heaters draw significantly more amps than a conventional water heater, most work best installed closest to the point of greatest use. if you are on a well you will not be impressed with a tankless as they can usually only raise the water about 40 degrees over incoming temp when operating, the pay back period for most tankless water heaters is over 15 years. google tankless heaters, I have read as much as i could but i can't remember which web sites i found the most helpful. I did decide not to use one in my new house because of the payback period and the poor performance on water flow and temp raise.

life begins when the kids leave home and the dog dies

Thanks speedwrench but we have public water and no well. We are looking to replace the old dying heater before it fails suddenly. I've researched tankless systems but was only wondering if someone knows of informational websites (not sponsored by manufacturers) because I'm sure I don't know everything about them.
So we would probably need a dedicated circuit just for the tankless system in out circuit box? (we have the capacity- just wondering)

typo on my last reply: I meant to ask,
So we would probably need a dedicated circuit in our circuit box just for the tankless system? (we have the capacity- just wondering)

yes you would need a dedicated circuit just for the tankless:if you are using a electric tankless, if you use a gas fired tankless you would not necessarily need a dedicated circuit. the gas fired tankless heaters are the most efficient kind of heater. everything that i could find out said that payback was very long and most new heaters are so efficient that temp drop over 24 hrs is rated at only 5 degrees

life begins when the kids leave home and the dog dies

Hhhmm..I was looking to get a propane powered tankless water heater. I was told the opposite about well water. I was told that the temp only dropped so far in the well water and the Tankless water heater would have no problem getting the water up to temp. I guess I have to do more research.