Trade E-PL2 for NX100? your take on this please.

I have a NX10 (same sensor as NX100) and the other half an EPL2. At low ISOs with post processing, there's no beating the larger sensor. But your specific bugbear was to do with high ISO performance in low light so that's what I'll base my answer on. Also, before we start, you're using a slow kit lens indoors. Get yourself a fast prime before coming to any final verdict.

My NX10 is perfectly fine up to ISO 800. ISO 1600 ideally should be post processed but you an get away with JPEGS if you're not fussy. I avoid ISO 3200 whenever I can and use fast legacy glass instead. Between ISO 800 and 1600 is a mystery to me as this range is not available in the manual setting on the NX10.

As for the EPL2, I feel that resolution and noise performance is about equal at higher ISOs with the JPEGS. And its the JPEGS that is where its at with the ELP2. Olympus just has their jpeg engine so spot on- colours are vivid and evocative, sharpness is better retained, auto white balance is far better, exposures perfect. I often feel I have to delve into processing with the NX10 but with the Oly I really never have a great urge to do the same. Auto ISO is also very well implemented- it goes right up to 1600 (rather than 800 with the NX10- not sure what it is in the NX100 but I think it's the same) and it always seems to pick more sensible shutter speeds in programme or aperture priority modes. I mentioned fast primes earlier- EPL2 + Lumix 20mm 1.7 is just heavenly for low light. If you really want ISO 3200, then check out the grainy film filter. Yes, the Samsungs have a B&W filter as well but the grainy art filter my Olympus is just so much more fun and actually negates the deleterious effects of high ISO grain. Finally, Oly has sensor stabilisation- VERY handy for low light.

I love my NX10, mostly because its just so damn ergonomically divine but I have to say the EPL2 is one fine camera. It ain't bad ergonomically speaking either (the best of the Olympus PENs in my opinion) and the lens line up for m43 is just getting sweeter and sweeter still. Don't turn into one of those serial system switchers constantly looking for the perfect system that just doesn't exist- both the NX100 and EPL2 offers far more than what the average photographer needs to have gallons of fun with their photography. Stick to the EPL2 for at least a year, get yourself a fast prime, and then let us know how you got along.

P.S. By the way, none of my comparisons are objective in any way. Much of it is influenced by taste and entirely based on real life usage (well fancy that!) as opposed to lab testing.