I currently have both. I'm a longtime GR user (you can see a lot of my shots in the threads on this subforum) and I bought the X70 to try out after handling it at CP+ a couple weeks ago.
After four days using the X70, I still prefer the GR. The X70, however, is a spectacular camera.
WHY I LIKE THE GR BETTER: 1. I like the GR's JPEGs and even its "film simulations" better.
When I was primarily shooting my Pentax and Nikon DSLRs, I always shot RAW.
Always. But the GR changed that for me. I fell in love with the Positive Film JPEG preset and I've shot pretty much exclusively with it (with occasional detours to High-Contrast B&W) since. The X-Pro1 is the only Fuji I've used extensively before this (I wrote the review for Adam's other site, camera-enthusiast.com), and I liked its film simulations well enough back then. But I've played with the X70's simulations pretty extensively and I don't like any of them as well as Positive Film (not even Classic Chrome!). Then there's the actual quality of the JPEGs. I guess I just don't like the X-Trans look, but the JPEGs out of this camera look a little muddy to me at 100% and just generally aren't as crisp as my GR shots. There's also a surprising amount of NR at relatively low ISOs. I'm sure that can be tweaked, but I've never been one to do that. The GR just works for me out of the box and that's what I want. Obviously, this is very personal.
2. I like the GR's controls better.
It may be that I've just been shooting the GR for too long, but the X70's manual controls (while undeniably
cool) just tend to get in the way for me. They're also not laid out as well. The left button on the d-pad, for instance, is right up against the edge of the tilt screen, which makes it really hard to hit. The playback and trash buttons are way too small and finnicky. The X70's touchscreen is nice for tap-to-focus, but I'm a center point/focus and recompose guy 95% of the time, so I don't get much use out of it.
3. The X70 feels too nice.
This is probably dumb, but I handle the X70 really carefully because it's so beautifully made that I'm afraid of damaging it/scratching the paint/etc. I hate the lens cap—never thought I'd say that, but I love that I don't have to worry about stashing one when I use the GR. The GR (strangely) feels more rugged and reliable, like I can just throw it in my bag and not worry.
4. I really love the GR's horizon level.
Again, minor and maybe dumb, but I love the fact that the GR's level does both roll and pitch. The X70's, in contrast, only does roll.
WHAT I LIKE ABOUT THE X70: 1. The screen. I think the GR actually has the better display, but the articulation of the X70's screen is a real godsend for off-angle shots.
2. It's beautiful. Going back to #3 on the dislikes, this thing is
gorgeous. 3. Like the GR, it's very customizable. You can customize a total of 8 function buttons, plus the control ring around front. Pretty impressive.
4. The AF is indeed faster. This isn't a huge deal for me (see above comments about being a center point/recompose shooter), but there's no denying that the X70 has an edge here.
5. The electronic shutter is a big plus. The GR's built-in ND filter more or less does the same thing w/r/t wide-aperture bright light shooting, but being able to shoot completely silently is pretty awesome.
SOME PHOTOS:
Here are some shots from the X70—all SOOC JPEGs tweaked in PS.