The recent Tenacious vs RAT1 thread got me thinking, so I decided to pull out the RAT1 and pocket it today.
I've always thought of my combo bladed AUS-8 RAT1 as a "camp" type knife and I still do but there is certainly no reason why you can't carry it as an EDC. It fits/feels better in my hand than the Tenacious but it's heavier and more noticeable in my pocket. The RAT1's blade is is slightly longer and shaped better for heavier and more varied use IMO, as would be expected on a hike or camping trip.
The use of AUS-8 vs 8Cr13Mov has been discussed on the Net and the general consensus is that the differences between them is negligible; they are both durable "enough" and can be easily sharpened w/a pocket stone. A D2 RAT1 would be more durable but would be more difficult to resharpen, may be be more prone to rust and is also a bit more expensive than one using AUS-8.
I'm not a blade snob and have a lot of knives w/very expensive premium steel but prefer blades that I can easily resharpen myself. So, my personal preference for the RAT1 is AUS-8 over D2.
After carrying the RAT1 for a day, I'd still prefer to carry the Tenacious for EDC use because the Tenacious feels smaller/lighter in my hand/pocket and its blade shape is sufficient for normal daily use. On the other hand, I'd still rather carry the RAT1 on the trail. So, my general opinion about these knives remains unchanged but for about $30 the RAT1 is hard to beat regardless of how you choose to use it.