I have a little cheap advice. Before buying the rebuild kit look the head over very carefully for any major parts that are broken, cracked etc. Then try loosening all the fasteners to make sure none are stuck. If it passes this inspection then the rebuild kit makes sense. If it doesn't then you saved $50 towards a new head. Rebuilding heads is a necessary evil, no matter how much you spend for it. Taking it apart occasionally and checking that everything is okay is not a bad idea. One that hasn't been apart in a really long time often won't come apart without breaking something.
Gary H. Lucas