I've been submitting prize crosswords since about 1971. Every week I submit 13 or 14 solutions (14 only when I can finish the Listener). I tackle them in this order.
1. Spectator(Won £30 1st time I entered Nov 2010)
2. Sat Times (Won twice)
3. Sat Guardian (Won several Dictionaries)
4. Independent (Won OUP books many times. I always rate the Independent as my "most likely")
5. Observer Everyman (Won once)
6. STimes (Won 2 runners up Cross ballpoints)
7. IoS (Won Oxford dictionaries several times)
8. Observer Everyman. (2 Book tokens)
9. Times Jumbo Cyptic (Never won)
10. IoS Beelzebub (again several wins)
11. ST Mephisto (3 wins in 40 years)
12. Observer AZED (Won plain twice, had 2 VHCs in the clue setting competition, including the MM crossword in 1999/2000
13. STelegraph EV (only recently done these. No wins)
14. The Listener. (No wins. Lucky if I complete. Longest run is 10 completions in a row.)
I have a kind of Crossword OCD, which leaves me bereft if for some reason I can't do this every week. When I think of the stamps, I console myself that it is a small price to pay for staving off Alzheimers.