The best thing about Lumia is, even their cheapest phones run "fastest" in basic everyday tasks, like social networking, emailing, Tapatalk, YouTube, web browsing etc. But the Samsung entry level phones (like J1 ace) cannot even do that properly, they lag, stutter and freeze too much every now and then, refusing to do even basic everyday tasks. J1 ace will be very slightly more faster than your semi ancient Galaxy. Lumia has the biggest advantage here.
But Microsoft needs to lower their sky high prices, nothing good will happen to Microsoft until it reasonably prices their products and fill the app gap quickly. There is still too many popular apps missing in Windows store, as I kept a Lumia 540 for more than a week for testing. I don't care about other useless apps much, but it should atleast have the most popular apps!
One of the best thing about Lumia camera is, it even allows manual shutter speed adjustment, which most Android budget phones don't offer. It's a very helping feature for advanced photography and i was shocked to find out this feature on Lumia 532 and 540!