I have quite a few Rada knives. I think the first one I got was the paring knife and I love it. Has a beautiful curve to it. I do find when it has a good edge on it, it seems to keep for a long time, but that really depends on what you are using it for.
Keep in mind I also have many others, lately have gotten a couple of President's Choice - they also seem to keep their edge. BUT again, what you use them on or for. How comfortable it is in your hand is very much a part of it too.
Had an old sharpener with 3/4 wheels on either side which did wonders with knives. My dad was good with a steel, my BIL uses another knife (amazing to watch and they are sharp!), my mom used a stone and the multi-wheel, I started with the multi-wheel (which has disappeared) and now use a Rada single wheel. Does an amazing job.