Right, I've had the Karrimor Excel Duel shoes a month now and done about 50mi of proper xc in them so feel I can give them a proper review. The shoe has deep lugs on the sole and i did not slide in the mud going up or down the steep hills in my area. The rock protection hard plastic in the arch of the sole also worked well and I felt confident that on rocky trails I wouldn't injure my feet. BUT, when you first get the shoes out the box you can tell the uppers on them are not very sturdy and sure enough after 25mi (not even a marathon) run in them I noticed both sides of the toe box on both shoes were starting to rip, after 50mi they now have 2cm rips on both shoes. I have also replaced the insoles of them with ones from my brooks gts's as they might as well of been made from cardboard. I will still continue to wear them until they break as they are comfortable and do the job, but I'm afraid that probably isn't gonna be too long. Most running shoes last 300-600mi, 50mi is just not acceptable.
I have run about 7yrs now & done 5 mara's & found Karrimor clothing to be the only cheap decent running gear about. The tee's & shorts lasted me +3yrs without falling apart. Saying this I have been the really annoyed on the karrimor shoes/staff in SD though, selling shoes indisciminately to people that don't know their gait WILL cause injuries (put a message on SD's Facebook, but it was swiftly removed. I totally relate to some convo's on here, although personally I don't want a springy cushiony trail shoe, more a hard protective one. Anyway, I normally run in brooks gts's, but the trail version is too narrow, asics trabucco gave me blisters, & every other shoe I've tried for the past 6 months didn't feel right. So in desperation tried on several Karrimors & 1 pair felt ok (excel duels?) I'll report back in a week on what they are like.. 5yrs of buying decent trail shoes that STILL weren't right for me is getting beyond a joke!!!
Yeah I wouldn't put any unnecessary pressure on yourself by entering more than one at this stage. Part of the fun of your first marathon is saying "I'm never going through that again!" at the finish line, only to find yourself searching for another one on the internet a week or two after, and getting those twitchy fingers to press enter for your next race.
It's my opinion only, and many people do it differently, but I like to reward my 4 months of focused training with a couple of months after the race without any specific goal. This way I can have some down time and enjoy my runs/spend quality time with the family, whilst recovering for the next marathon schedule.