Well, It maybe depends are you making a tutorial or a battle movie from mount&blade or something. Fraps is good but as you probably know, you can only capture for 30 seconds with the non-registered version. Game cam is a good one too.. Hypercam maybe? Im not very familier with hypercam though... Camstasia is a good one. Many tutorials what I have seen, have been captured with camstasia. But for making a battle movie or something. Well, it can be good but I dont know how it works with different games. Maybe better for making tutorials. Example: modding tutorials etc..
Your FPS drops when you capture footage in any program.
In Fraps, if you are able to handle what you are "capturing", IE: all units on the screen, graphics, effects, etc., without lagging, you should have a solid 15-25 FPS. If you are unable to capture everything on the screen, because of graphics or too many units, your FPS will stutter up and down. If you are getting 5 FPS, you need to check the settings and make sure Fraps is set to 25 FPS. If it is, and you are still getting 5 FPS, you either (in most cases) 1, need to defrag your HD, or 2, need to get a better system/gfx card that can handle it.
Edit: Just to clarify. I run M&B with 150+ FPS, but when capturing in Fraps, you still drop down to 25 FPS (depending on what FPS you selected in the options) which is considered a "smooth" capture as far as fraps is concerned. You really don't need to select any other FPS than 23-30 but if you have trouble capturing, you can always set the FPS to 15. Anything less than 12 FPS in M&B will not look decent at all.