The advantage to the UTM is that instead of having to check out 3rdR, Crusade, Imperial Starfire, SM2, Alkeda Dawn, ISW4, and Insurrection and then sort out which one is the correct form of the object you could look in one place and get the information you want.
Also even if the rules don't change...for some systems different parts of the rules are in different places. PCF are outstanding for this: 3rdR has some of the rules, Imperial Starfire others, SM2 has other parts and I think there are changes in Crusade and ISW4 covering higher tech PCFs. And not all changes are very clear...for example the Q capacity of small craft with respect to the csp cost of an airmobile PCF. Marvin is apparently willing to sell the UTM and I think it would be worth exploring that option just to save you a lot of hair pulling as you try to sort out exactly where the exception to the rule is stated.