In terms of courses still available, I thoroughly enjoyed my SR Leadership Course and got one hell of a lot out of it. Beware of becoming focused solely on courses, though, going into an operational billet and putting the training to good use is far more worthwhile.
Not RNR but the best course I have done in the mob was my POLC at Whale Island, now called SRCC. There were points that, at the time, I didn't enjoy so much, but looking back now, I had an outstanding time.
Best course - two week fork lift truck course at Faslane. Flew up, top hotel (no accomodation available), they cancelled course before it even started. The remaining 13 days were tough, but I pulled through. :grin:
Best deployment - month in Canada, leading an AT expedition.
1. BSSC - where I met the PO Stoker
2. POLC - hard work but a right laugh
3. Merchant Navy Acquaint - we rated our visits to various merchant shipping related companies not by their presentation but by the quality of the tea and biscuits!
4. NCAGS conversion - the course that converted us from Ops(HQ) to NCAGS - it was like being on course with every friend I ever made in the RNR in my branch
After CTC, which I actually enjoyed, it would be the abseil despatchers course for Wessex and Sea Kings (great fun ... we used to take Yeovil Wrens up 200' and despatch them. Great fun in the bar afterwards) and after completing my para course the short course I did for water jumps.
Never took the course but was involved in its instruction - it was a battle to remain motivated enough to turn-to as an instructor, I hate to think what it was like for the lads/lasses taking this course!