well in JKD instructor is 90% of it, two diffrent instructors can be totaly diffrent, I know next to nothing about tiger kung fu (only what I have read and who knows how much of what I have read is acurate). My advise would be to practice both for a short time if posable, maybe go 2 or 3 months in each so you get a feal for the classes and sit in on the advanced classes to see what they are doing and ask if you can spar with some advanced people just for practice to see how they work things.
Because alot of jkd instructors have learned more than jun fan gung fu and alot of the time these other aspects are incorperated, and additionaly because jun fan is largly composed of techniques that have been imported and modified from various arts, it may not be easy to tell you what you will get in the class.. if you could post an instructor lineage it might help, also ask your jkd instructor just what aspects of jkd (and other arts) are trained so you know what you are getting into.
If your JKD instructor is like mine you may be learning more than one art (kali in my case with a little silat) and that changes everything. As to what jkd is genneraly like? wink of a mix of wing chun (in fighting) western boxing and sevate (french boxing, look it up off google if you don't know what it is) genneraly ground fighting and standing grappling ranges are trained to be areas where you probably don't want to go (though again it deppends on how you like top fight and how your instructor teaches) and if it's just jun fan you are learning I don't think weapons are trained, but I'm not 100% on that.. basicly speaking JKD is about efficiencie, directness, and speed. It's about ending a fight with the leaste expenditure of energy in the fastest way. there will probably be an emphasis on destructions and lead side attacks, alot of shin kicks and alot of lead straight punches to start things off, but it should go more in depth into boxing, kickboxing, sevate, and wing chun depending on your instructors back ground, some other common arts that are cross trained would be mauy thai, silat, kali, and BJJ.
Also a posable consideration for the JKD instructor would be their lineage, are they from a JFJKD person or a concepts person? may change little things, and maybe you wanted to train with one or the other but hsould change all that much. just make sure they have alot of knowledge or al you will be going is kickboxing with shoes on.
So basicly.. if you liked karate and want something like it, you are probably better off with the tiger, probably would be more simular (not knowing anything about tiger and not knowing your karate style/school I could be off). If you wanted something a little diffrent than the JKD might be a healthy change of pace.
