I cancelled mine last year (had donated 25 per month since 1996)
got really pissed with them for the following reasons:-
1. Non Profit Org running like MNC
2. Non disclosure of mgt salaries (fat pay cheques and 1st class
travel)
3. High profile NKF fund raising shows on TV (WIN condo, car, BIg
$$$ strategy)
4. Harressment by tele marketers (till i lodged an official
complaint)
5. Enrolled me in some "club" thingy, and sent tons of reports,
letters and invitation cards in GOOD quality paper and cards. waste
of $$$.
6. Annual report printed in colour
7. Huge reserves. Yes they need them but XX millions?!?!!?!?
8. Arrogant behaviour: "We can raise more money, we got the brand
name!!! attitude
9. Depriving other NGO of funds / donations
10. Partnership with mediacorp and singtel (always wonder how much
are their cut)
11. Sueing reporter and SPH for spilling the beans 
For those out there, please consider channelling your donations to
other NGO or non profit org. NKF can still survive from donations
from the less informed pubic! auntie and uncle type!?!?!?