Beer will still taste 'green' in the keg if you don't give it time to condition on the gas. When you bottle you're restarting fermentation to get the carbonation so that's probably what you're referring to as the flavor change. Kegs will sort of do the same but what you're tasting is just green unconditioned beer as opposed to (re)fermenting beer in primed bottles. Bottled beer then needs to condition after the carbonation fermentation has ended.
There are a few different ways to carb your beer in the keg so you have to figure out which one is right for you and how quickly you need/want to be drinking your beer. There's the set it and forget it method (which is sort of like bottling time wise), the force carb method, and then hybrids of each of these methods.
My packaging routine consists of: After fermentation is complete I take an FG reading at room temp, then cold crash the carboy of beer in my fridge to drop out all the yeast/dryhops. After 2-3 days of cold crashing I rack the beer into a keg, purge the oxygen, and set it to 20 psi (if the style of beer calls for 2.3 or so c02 vol. and less psi for stouts and the like) for 3-5 days, then purge the gas and set it to serving psi, which to my liking is about 5 psi.
I'm on a 2 week, or so, cycle. I usually brew every 2 weeks, sometimes more, and I have 2 kegs. I keep a regular gravity beer and a high gravity beer on tap, usually, at all times. 2 weeks works for me and my rotation because it's just me drinking the beer and I can usually go through 4-5 gallons in that amount of time. I do occasionally run out of homebrew and have to wait a few days to a week for my next brew when people come over and drink on my kegs. It's not really a huge deal though. It's taken me about 6 months or so to get my system down and how long each step takes. Just play around with it and you'll get into some sort of routine that fits you. Good luck!
