TS, I'm using using the 2003 E-1 and the 2007 Nikon D3. I just shot a wedding and one of the guest said to me "upgrade your D3 to D4s la", fact is, if I had money, I most probably would. But at the same time, my D3 has been serving me well, it and I have been through a lot together. Literally been through fire and sea water. Survived my drops, banging into it, stared down the barrel of a gun too, so I won't bother changing it until it's last shutter movement.
My point is, just cause the E-M5 is older, doesn't make it any less of a suitable camera. Sure, the Sony a6000 and E-M10 have their own merits and supposedly will be better because they're newer, but at the end of the day, does the E-M5 suit your need? I like the lens the elite E-M5 comes with and the E-M5 is, imo, similar to the E-M10 and has weather sealing and magnesium body to boot! But of course, I found that the E-M10 is better at handling (without grip or modifications to it). But this is all personal to me la.
If someone has already said it, I'll say it again, if not, I'm saying it now, get up, get down to a shop, ask to handle and then you'll know which one feels good in your hand. These days, without comparing picture with picture and actually staring hard at it, most people wouldn't notice the difference, especially if you've post-processed it. I recently used a 5D MKII with TS lens, i liked the interface and the screen, color was so so, the only thing I hated a lot was the ergonomics, I had pain in the back of my hand after the shoot, and the kick was, almost all my photos were shot on a tripod.
At the end of the day, ts, remember that "one man's poison is another man's meat", as already mentioned, the good lenses from Sony are expensive, and despite the difference in prices, the Zuiko lenses quality are just as good if not better. When Wonglp and I did the 25mm f1.8 lens preview with the E-M10, we were both amazed at the sharpness. I believe can see the veins in my eyes