We agree wholeheartedly with Bill, each cham has a distinctive personality.
We have a fair-sized breeding colony (over 100 enclosures for adults), and 60% are pardalis. 25% are veiled, with the remaining portion consisting of deremensis, rudis, quadricornis, jacksons, and melleri.
Of all, we feel that the veiled have the most aggressive personalities. Once they reach sexual maturity, many of them go through personalities changes and become less friendly. There are exceptions - but the average is represented.
Pardalis babies can be friendly from the very beginning (as with veiled babies), and can continue to be friendly throughout their lives. We have had some for over 3 years and they are still hand tame and personable. This is a generality - as there are exceptions with pardalis as well. We have had a couple that have never tamed down (but we got them as adults). We have only had one baby that remained skiddish into adulthood.
We don't know what age your chams are, so we cannot offer any advice other than waiting a while before making the decision to get another pardalis. If the one you have is skiddish, you might try some of the techniques for hand-taming. You may also examine the habitat - sometimes newly decorated "digs" can perk-up a cham. Pardalis can be awesome chams to handle - some can be active like crazy too. Many like to be hand fed (treats especially), so don't give up.
However... keep in mind that chams are not the usual ideal "pet" - they are more of a "display animal" (although we hate to use that terminology). They are marvelous to be around - even if they don't greet you at the door when you come home. 
Best regards,
Morgana - Reptayls, Ltd.