I've tried at least some of all of these systems.
TLT's: great! Very beneficial for posture, stability, balancing what may get unbalanced by more traditional weight work. Start with FYC and SIM and get the other two later if you want (the other two have a steeper learning curve, IMO).
P90X: my best fitness investment in a long time pre-TLT's. Tony has some functional fitness takes on traditional strength training. I love the way he sequences the weight work (push-pull or circuit) so it's more time efficient and effective. I needed more lower body to keep my booty where I want it to be. Not tough cardio, but not meant to be, in order to maintain maximum muscle.
Turbo Jams: I previewed "Ab Jam" and some other workout (with weights) but haven't tried them. Some of the moves look unsafe (like doing a 'hip wiggle' while pushing up from a squat--seems like the back would not like that). Kind of uncontrolled, IMO. NOt enough actual kickboxing for my tastes.
Cardio Coach: I use this on my rebounder and Transfirmer. Excellent (just shut off the CD player at the end before you hear one of Sean's jokes--annoying). Good if you have some kind of equipment at home and can figure out what to do while listening to it (I turn the TV on with no sound and subtitles and 1/2 watch it). I'd start with volume 3, then add on (up or down) from there.