The Sea King is a really excellent kit. I haven't built mine yet so I can't comment on the fit but the surface and interior detail look great. The decal sheet is extensive with a lot of minute markings. For some reason, this kit seems to be really inexpensive. I got mine for about $11 US retail and it usually sells for less than $20. This is an excellent bargain! Revell has posted the instructions on its website: http://www.revell.de/manual/04411.PDF
The AH-1W is an Italeri reissue. Instructions: http://www.revell.de/manual/04415.PDF
The Tigre is a new mold and the reviews indicate that it is a very good kit. Instructions: http://www.revell.de/manual/04485.PDF
If I had to pick only one, I'd DEFINITELY go with the Sea King!
Martin IPMS 44668