I am probably the best person to answer this.
Yes private practice in general makes more right out of the gate than most academic positions. In the long run though, I would bet that seasoned attendings make similar incomes to hospital based partners. Remember partners have to pay for everything out of their income (i.e. the corporation). So retirement, healthcare, educational fund, etc... all come out of the corporation. And moreover, even in scenarios where private practice people make considerably more, chances are they are working harder in terms of caseload. With all due respect to LADOC00, (who claims to sign-out 45 minutes a day, drive an F40 and live next to Agassi and Graf in Tiburon) from talking to hospital based private practice pathologists, they work their asses off to maintain their incomes.
Besides, on average more income, private practice types get to do multiple activities. In addition to signing out AP, they might also manage microbiology or blood bank and also be involved with administration. Plus you also get the satisfaction of being your own boss in your small business, which you don't get if you go into academics (or non-academic mill work).
The advantages to academics is you just get to do pathology. It seems like PP types are so stressed out about losing their business. In academics, you just get to do what you love. You don't have to fret that the urologists will take your away biopsy business or that the GIs will for their own lab and subcontract the pathology. At least at most large academic centers that is the case. There is plenty of pathology with the internal outpatient and inpatient cases.
Also in academics you get to be part of the stimulating environment with proximity to research, world experts in multiple areas of medicine. And many academic medical centers are near the main campus making you truly part of a campus environment with all the accoutrements. Plus you get the stimulation of working with medical students and residents.
Now if you don't like any of those things, then that would be the advantage of going to PP.