For starters, I have always found the people on this forum to be more than ready willing and able to provide an abundance of help on just about every category there is from purchase, use and do-it-yourself maintenance... Second, as someone who owns an '06 Challenger 180, I highly recommend the boat, I bought mine with 12 hours, currently have about 170 and have enjoyed 7 yrs of trouble free fun (with the exception of my neutral switch). It's a great all around boat, easy to tow, store, room for plenty of people and gear, agile (once you get used to the jet function) and quick...basically fun with some creature comforts...
Obviously a boat with 130 hrs has almost 3 times the use as the one with 50, but both could be pristine, pride of ownership, responsible care and use says more than the hour meter reading. What extras are included? trailer, extended warranty, vests, ski's tubes?
I'm sure you know the NADA value is determined working back from the original retail prices, when new the options (snap-in carpet, sat radio, wake tower etc ) all added costs, so when maintained in good condition, they continue to maintain a percentage of their value making that model with those upgrades worth more used.
Bottom line is YOU need to make your own evaluation based on what you see and feel, not off something you pulled up on the internet Examine the boat inside & out, ask for service records, why are they selling it? Do a sea trial, if you don't feel you have the expertise to do a comprehensive survey, hire a pro to survey and evaluate the boat for you, chances are good you will save back that cost and possibly a lot more, not to mention the joy of owning / using a trouble free boat.
Best of luck and happy boating!