You will find the sacrifice far outweighs any of the downsides to the job. The only part I didn't like was the night shifts but if you prepare for them then no problem. Obviousely you cannot go out every friday and saturday night with your mates but when you are off for the weekend then you look forward to it more. You can also go shopping without the hussle and bussle of saturdays when everyone else is. You will soon get used to shift work and I'm sure you'll find it to be ok. Enjoy the job it's great, if you do not like shifts then there are plenty of opportunities within NATS to work 9-5. If you also plan your leave well in advance then it helps. Like you say 180 days working per annum, not bad. A good wedge in your hand every month, not bad. Discounted holidays through UKATTS, not bad. Discounted flights through the Guild, not bad. All in all bloody good. Concentrate and pass your exams, validate and then decide.
Rgds
ILS 119.5