I've tried Transfer Factor which is better than colostrum because it is much more powerful.
The one I used wasn't that good although I did feel ok slightly better when I first started it.
I'm going to be starting another one once I get some other things going. The one recommended to me was Researched Nutrionals Plasmyc. That's a bit pricey so I may try the Multi-immune. I found some people talking about them on Pro Health and except for one person, people had great results.