Whenever the WH is located a long ways from the point of use, it takes time to purge the lines of the room temperature water there, unless it was run recently and some is still warm. The alternative is to recirculate the water like is done in large buildings. But, with many tankless systems, it can either void or significantly shorten the warranty on the unit.
The tankless systems also have a minimum flow before they'll turn on, so it may never be enough if you have the faucet set to what normally would have been warm. Once they turn on, they may stay on until the flow stops, but getting an initial warm may be tougher.
There are a few recent threads on similar issues...check this forum and read a few.
But, once you do get hot somewhere, it should be about the same temp.
The only other thing I can think of, and it normally isn't an issue with new faucets, is if one of them is defective, and is effectively creating a cross-over - this would dilute the hot, potentially considerably. Do you have anything like, say on the washing machine that connects cold with the hot? Try shutting the valves to the washing machine off and see if it makes any difference. It shouldn't, but it won't hurt to try.
It may help to also know the brand and model of the tankless unit.