We currently own an Gen 4 Outback (2010 2.5i Premium) and a 2013 RDX Tech so I can offer some insight.
I love both cars but for different reasons. Outback feels slightly bigger in the passenger compartment and clearly has more cargo room behind the rear seat. It has more overall utility and I don't feel guilty taking it offroad or loading it full of gear, lumber, etc. I also love it as a road trip car, we've taken it on several vacations and it always works well as a highway cruiser.
The RDX I love for it's refinement and technology. I thought the Outback was a relatively quiet and smooth riding car until we got the RDX. For those who don't know, the 2013 RDX is a complete redesign (much more attractive styling than the outgoing version, IMHO) and now has the 273 hp 3.5L V6 from the Odyssey, 6 speed tranny, new suspension, etc. Butter smooth, quiet and plenty of power. When I say quiet, I mean QUIET. It's just a more sophisticated, refined car than our Outback, and, given it's pricepoint, it should be (there is about a $10K difference between the MSRP of our two cars, $28K vs. $38K. As I mentioned before, there isn't nearly as much cargo room as in the Outback with the rear seat up, but with the rear seats folded down, there is actually quite a bit of room...feels comparable to the Outback.
Not having owned an R6 with the tech options, it is difficult for me to do the fair comparison of the relative value of a R6 Limited with Nav, etc. to an RDX. The RDX base starts at $34K (includes everything but the Tech Package and AWD) and the R6 Limited starts at $32K. The Outback will have the better AWD system, as the RDX moved away from Acura's SH-AWD system to a less sophisticated front-biased, system. I didn't even buy it since we have the Outback for the really bad stuff and the RDX has FWD with traction control and VDC which will handle 95% of our bad weather here.
It's unfair to compare the two cars on features since our RDX has every option available except AWD and our Outback has only they typical Premium features (moonroof, HK stereo, AWP, etc). If you really loaded up an Outback, I imagine you could get close in terms of technology available.
All in all, the cars really feel as though they are meant for different purposes. The Outback is a good overall dependable and safe vehicle that does many things well. You know it's going to get you where you need to be regardless of conditions. The RDX, on the other hand, pampers you. The Outback we would use to go kayaking, biking, run to Lowe's, etc., the RDX we would take for the drive in the country, take to a winery, out to a nice dinner, etc. I think if one is only looking at objective measures, the Outback is the better overall value. However, from an overall experience standpoint and with more subjective considerations, the relative value is closer. I don't think you can go wrong with either...I enjoy them both very much. They both put a smile on my face, just for different reasons.