I am going to retire an electric water heater that I installed at 1986. I am considering going tankless natural gas. It appears to be much cheaper to run. Does anybody have any experience with the tankless water heater systems? any help would be appreciated 

I have one, no complaints. I think you’re supposed to flush it every couple of years. We’ve lived in our house for around 9 and only flushed it last year but the guy said it looked fine. 

Got one about six or seven years ago. No complaints. Water heats up quickly and lasts.  We do descale every year as suggested by the installer. 

i had to replace my water heater a few months ago and did homework on them then. the gist of what i gathered:

the tankless units are more efficient, but they're also significantly more expensive to buy/install... so it might take several years to break even and reap any of those cost savings. the energy savings directly correlate with how often it has to make hot water. if you have a large home with lots of users, it won't be nearly as efficient as you'd think.

so instead a better question to ask yourself is:

do you find yourself running out of hot water with a tanked water heater? if no, buy another tank. if yes it may make sense to go tankless...especially if your existing water heater is in a cramped space and you can't go bigger.

in my case i just opted to get another tank.

edit: oh, you might want to poke around on your gas providers website. sometimes they provide rebates/kickbacks if you get something energy efficient (tanked or tankless)

My father in law has both. 

He is retired now, but he used to do HVAC so he knew how to install water heaters too.

In his house he installed a tankless but also left his tank in almost as a backup hot water resevoir. I am not sure if he put them in parallel (either or) or in series. He likes the tankless. Its just him and my MIL though, so like said above if you have a lot of water users it won't be as efficient as you think.