Shoe talk - yay! I was on the Salomon Flight Crew for 5 years and still have a minor level of sponsorship so I'm obviously biased toward Salomon. However, I've had a pair (or 3) of almost every kind of Salomon shoe so I'm able to compare them.
Btw I read a study concluding that runners who rotated through 3 or more different shoe models reported fewer injuries so I try to mix it up a little. For what it's worth, with a closet full of Salomons, these are my first choice shoes for different activities:
ADVENTURE RACING (mix of terrain and pace, often off-trail, paddling, swamp wading, etc.)
- Salomon XA Pro 3D. Yes, it's heavy but it's durable, stable, has a good tread and offers good protection. If the trek portion of your adventure race is 100% on trails where you always plan to run, then a trail running shoe would be more appropriate. As far as I know, the Salomon Global Footwear Manager (Phatty on Attackpoint) still wears XA Pros for expedition AR.
http://www.salomon.com/caus/product/xa-pro-3d.html...
If you look at the links I'm providing, you'll see that Salomon rates each shoe on Durability, Protection, Weight, Drop (subtract the two numbers beside Midsole Height), etc. So you can do a comparison by looking at the shoes you're interested in.
ORIENTEERING (30 minutes to 5 hrs, off-trail, scrambling) - S-Lab Fellcross 2. Great tread, relatively low drop (4 mm), very light. I don't use these for long runs - too light. They are best for mud and soft conditions. (I haven't tried Fellcross 3.)
http://www.salomon.com/caus/product/s-lab-fellcros...
TRAIL RUNNING (mixed surfaces, up to 125 km so far!) - Speedcross. Great tread, feels "precise", light, decent protection and cushioning.
http://www.salomon.com/caus/product/speedcross-3.h...
TRAIL RUNNING 2nd CHOICE - S-Lab XT6 Softground - Very different fit (a wider shoe) so it's nice to mix it up. More protection.
http://www.salomon.com/caus/product/s-lab-xt-6-sof...
TRAIL RUNNING WHEN I WANT TO FEEL LIKE KILIAN - Any of the "Sense" line. I have the Sense Pro.
http://www.salomon.com/caus/product/sense-pro.html...
If I want to treat myself some day, I'll get the S-Lab Sense Ultra Softground but I'm really not a good enough runner to deserve them!
http://www.salomon.com/caus/product/s-lab-sense-4-...
ICY TRAIL RUNNING - Snowcross or Spikecross, depending on how much snow there is.
Fellraisers are designed for muddy, wet conditions. They're light and have an aggressive tread. They have a very tall toebox and after I got blisters under my toenails in a race one time, these were the only shoes I could wear.
There is a line of "CityTrail" shoes that are designed for runners who run on roads and trails in the same outing. The X-Scream or XR Mission are examples of these shoes. I haven't used them much since I rarely run on pavement.
Hope that's helpful and I don't intend it to sound like a commercial but Silkychrome suggested that I jump in for some shoe talk! :)