In reply to EarlyBird:
I've snapped both of my achilles tendons!
First time back in 2006, I was stuck in a cryo cuff, give loads of lager and then after 3 days casevaced back from the jungle in Brunei. Straight into theatre and operated on. In a cast for 4 weeks on crutches then another cast with it slightly moved for 2 weeks. Then into an air boot for 12 weeks with the foot being slightly raised every 2 weeks until it was at 90 degrees.
After that, mild physio for about a month and then into proper rehab sessions (I was miltary at the time and it was proper hands on rehab once a day for at least 90 minutes, agony!) My rehab went on for 4 months and it took me at least that to then go for a very short run. Back to running/climbing etc properly a year near enough to the date of the accident. (14 months after op did the Marathon des Sables without any tendon problems)
Second time, 2013, no surgery as the guidelines had changed but with exactly near enough the same treatment as above. Didn't go back to running as wasn't in the military but managed to again after about a year get properly back into climbing, skiing etc.
All this time past now and I still get flare ups with tendonitis and in my case, if I decided to take up running again then according to the Consultant, I'd have a high chance of one of them snapping again. Maybe this is just because I'm a big old unit at 6ft 3 with a big upper body either way, patience is the key and if you rush it, you're going to be buggered.
Personal opinion from someone who is very active and has had conservative treatment and an operation, I'd go for the operation any time. My achilles has a fairly big amount of scar tissue but it is definately stronger than the non operated one.
Good luck and don't rush it.
Den