His +/- may be ok but it's not that good, no ones is really. Tucker's is more impressive given that he's missed 4 games so far and is playing fewer minutes than last season. Kieff is not the long term answer at the PF spot and I'm afraid Hornacek & McD have him slotted there for the foreseeable future, unless of course a "star" becomes available. Even if a "star" becomes available we're overpaying backup forwards. Their extensions made it to where they are no longer positive tradable assets to pick up a star in a deal, at least not nearly as good of assets as they were last season or without the extensions. Being on rookie deals and headed for restricted free agency together would have been easy to deal with since they were clear they wanted to stay together which would have scared some teams off from making a sizable offer to just one of them.
Markieff's rebounding leaves a lot to be desired. I'm really surprised he hasn't been called out as much as Channing was last year. It seems the only negatives everyone is calling out is that the 3 PG rotation isn't working that well and also Len should start over Plumlee. Regardless of what was going on with the team, winning or losing, while Channing was our starting PF everyone seemed to harp on his rebounding woes and statistically Markieff isn't really any better. When Amare was here he was also called out by posters for his "horrible" rebounding numbers while averaging 7-8 a game.
Frye averaged 28.4 minutes last year and pulled down 5.1 rpg, Markieff is averaging 30.8 minutes and only getting 6.4 rpg. Kieff is up .4 rpg compared to last season when he played 4.2 fewer minutes. That is a slight improvement over Channing, albeit a small one, but given the increase in playing time and decrease in rebounding by Plumlee and the starting SF position you'd expect it to be better, or at least hope it would be. I don't understand why he hasn't received the criticism that Frye received.
Plumlee is averaging 2.3 rpg less than he did last season (24.6mpg & 11.5rpg last year/23.2mpg & 9.2rpg currently), Tucker hasn't been starting and his rebound are down a little (30.7mpg/6.5rpg last year vs 26mpg & 6rpg currently) and Marcus is averaging the same as last season (22mpg & 3.9rpg vs 24.6mpg & 3.9). So if you look at the front court of the Suns, Markieff really hasn't been an improvement over Frye like some had hoped or expected. Kieff is definitely a more traditional PF than Frye offensively and defensively and he plays inside on offense more than Frye did so that should help with offensive rebounding but it's not.