Sorry I do not have any direct Catalina Direct vs West Marine vs ??? cost comparison data to share. But I do have some general lifeline modification / replacements thoughts.
For a good introduction to all the various fittings, et cetera that are out there, have a look at the Marine on-line catalog at
http://www.csjohnson.com. C. S. Johnson is a USA manufacturer of all sorts of marine fittings, life lines included. As you may, or may not be aware of, there are two classes of life line fittings: those that are swaged by machine and those that are hand crimped using a special tool. The machine swaged must be made in a rigging shop using an expensive machine (too expensive for the average boat owner who only does a small amount of life line work from time-to-time). The DIY folks (and the Catalina Direct kit) use a C. S. Johnson-manufactured hand crimping tool. And here there are two C. S. Johnson choices: one a $300 big lever-style crimper (for shops who do a lot of life line work) and a bolt-type crimper for those of us who only do a boats worth of line from time-to-time.
The do-it-yourself path is a straight forward method that should be able to be completed by anyone that posses a little tool experience and a little mechanical aptitude. All you need in the way of tools is a cable cutter and the bolt-style crimper. As to materials, you need the life line cable and hand crimp fittings. The procedure itself does not require taking precise measurements and then transferring them to the cable to be cut. Instead, you install one fitting and attach it to its stanchion mounting point, thread the life line through any stanchions it may be passing through on the way to its next attachment point. At this end, you mark the cable (according to instructions for the fitting), cut the cable, and, using the crimp tool, install the fitting. One lifeline complete!
Comments on the Catalina Direct kit: It has all the high-quality pieces and parts (and tools) you will need all in one package. And you can return the crimping tool for a refund. (The crimping tool in their kit has already been used by other kit users who then returned them.) On the downside, you are restricted to using the style of pelican hook they have chosen, and there are no "custom" selections, like adding a second gate somewhere along the run. Not sure by looking at their photos whose cutter they are sending you (there is a difference in quality out there - but since it is Catalina Direct, I would assume it is a suitable tool for the task.)
Comments on the DIY approach: When you make the investment in a good Felco cable cutter and the bolt-style crimper (both available from C. S. Johnson and others), you are prepared to make not only this set of life lines, but are also able to repair / modify any others down the road. I like having the capability to be able to do so.
Here is my approach that I have used on three different boats now (a Tanzer 22, a C&C 30, and a Capri 22). Purchase the cable cutter and bolt-style crimper. Buy a good quality cutter (Felco) - the first one I used was not as good a cutter and made the job harder. Next, design your life line system - add the style of hooks / fittings you want, add gates where you need them, et cetera. Get an idea of how much cable you need to order - get a little extra, nothing worse then coming up two inches short just because you were trying to save a few dollars. Order all the parts. Remember, you need to buy the hand crimp-style, not the machine swaged style. I get my part numbers from the C. S. Johnson catalog and then shop for price and availability at various on-line places (search by part number). Sometimes I have lucked up and found some of the needed parts in stock in our local West Marine store, but usually have to get them online from C. S. Johnson or another retailer of their parts.
Good luck with your life line project.
Edited to add a couple more thoughts:
If I remember correctly (and there is no guarantee that I do), in some years and on some models Catalina used a different thread in various places (i.e., A LH where others used a RH, and vice versa. Makes no real difference except where you are trying to re-use some of the old Catalina parts (e.g., a pelican hook) with a new threaded stud fitting on the new cable. If you are going to re-use older parts, just make sure the newer parts in that particular assembly will match up.
Whether you decide on the Catalina Direct kit (where you hand crimp the final fitting) or go the route of a custom DIY job where you hand crimp everything, obtain a couple or so of extra fittings (threaded studs or whatever is the cheapest). Then cut your OLD life line apart and practice installing these "sacrifice" fittings. The act of having a couple practices before the "real" thing will allow you to work out your technique, and give you some experience in the matter.
