Mike Trout
Albert Pujols
Prince Fielder
Miguel Cabrera
Carlos Gonzalez
Matt Kemp
Adrian Gonzaelez
Evan Longoria
Joey Votto
Matt Holliday
Adrian Beltre
Buster Posey
Ryan Braun
Andrew McCutcheon
Josh Hamilton
Giancarlo Stanton
There were off the top of my head...
All of these players are, easily, better than Justin Upton. Justin has been in the bigs 6 years and his best season was a 31 HR, 88RBI, .289 batting average year in 2011.
He's good, quality player. But to throw him in the "top 10" catergory is a pretty large stretch.
1st of all, i think we can all agree that RBIs and Rs have more to do with your lineup and lineup placement than the player (within reason, tyler pasternicky isn't going to drive in 100+ and score 100+ runs just by batting 3rd, but for the guys you listed and justin upton, i think we can agree that getting 600+ ABs in the middle of a remotely decent lineup should produce good R and RBI numbers).
2nd, after 2011, i'd have put upton ahead of trout, cargo, gonzalez, beltre, posey, mccutch, and stanton. i am talking about were he stood after his 2011 season compared to other player's 2011 seasons.
now factor in age, and i'd take upton easily over holliday, beltre, and hamilton.
then look at the number of guys that have been injury prone the last few years on your list (much like upton was last season): cargo, hamilton, posey (plus playing C increases injury chances), votto, longoria, kemp, etc. some of those were more freakish than others, but they all missed sizable chunks of a season recently.
not to mention, how many of those guys have had a down season or 2? especially when they were <25 and injured? do you think it would have been cheaper to trade for mccutch now or a year or 2 ago before he blew up? what about cargo? after 2009 he was a nice prospect with an OK track record in limited MLB action.
the simple fact is that upton at 25 has done more and put up better numbers and had a better single season than any of these guys from your list: beltre, mccutch, cargo, votto, gonzalez, hamilton (due to non-baseball reasons obviously), kemp, and holliday. longoria's 2009 and upton's 2011 are very comparable.
now note that i said he "dabbled at the edge of being a top 10 player", i didn't say he was 100% slam dunk a top 10 guy. but the fact that he was even in the discussion after his age 23 season puts him far ahead of the developmental curve of many of the players you listed.
to get ahead in sports, you have to get the talent cheap before it blows up. would you say upton should get a contract on par with fielder or pujols or cabrera right now? of course not, but he has the talent, has hinted at the talent, and you have to get him before he becomes the MVP candidate if you don't want to pay through the nose for him. i'd put upton right there with most of your list, and it wouldn't surprise me to see him outperform most of them any given season if he's healthy (which he wasn't most of last season).