C.C.
I'm a commercial construction manager, and I have quite a bit of experience with tankless hot water heaters. Yes, they are worth the investment. I would go with Rinnai or Takagi brands. Both are well made and hold up over the long haul. I would NOT purchase the Bosch brand (difficult warranty service).
A few words of advice:
1) MAKE SURE that you purchase the exact type of exhaust pipe specified in the installation manual. That is extremely important, and can cause your water heater to malfunction/will void the warranty if you cheap out and buy a non-specified type of exhaust pipe.
2) Set the water temperature pretty low (like 105 or less). It sounds counterintuitive, but these heaters work on flow rate. The ideal is to turn your shower on and have the hot water running full blast - your shower will come out the perfect temp and last forever. If you set your water heater at 120, you will need to mix cold water in in order to take your shower, and the flow rate might not be high enough to trigger the heater to turn on. So, just set the temp at "shower temperature" (whatever that is for you) and you'll be fine!
These are just a few things I've run across dealing with this type of water heater professionally. You'll love having a tankless hot water heater! They are totally worth the investment!