A- -->
A
Pretty good mon in general and lack of Feraligatr is a really nice thing for this Pokemon for a variety of reasons. For one, the best Pokemon in the tier doesn't take advantage of it and uses it as setup bait, and for two, it's a lot easier running defensive teams that this thing does well against. It's also a fantastic check to Houndoom (and almost every Electric-type), which is pretty amazing right now, which leads to my next nom.
A -->
A+
Really powerful Pokemon right now. Between its ferocious NP set that's terrifying for stall and access to Sucker Punch and good Speed that lets it hold its own vs more offensive teams, it's just overall very consistent and puts in work in almost every match. Has some pretty cool utility options in Destiny Bond, Taunt, and Pursuit which adds a more supportive feature to this mon. Only thing that holds it from S rank is the lack of bulk in my opinion, but otherwise, this thing is top tier without a doubt.
A+ -->
A
Rhyperior is a little too exploitable to be in A+. Two 4x weaknesses take a toll when many Pokemon that Rhyperior should normally beat or have no problems switching in on can employ a random HP or coverage move to rip past it. It's still a good Pokemon, but sometimes losing to the stuff that it's supposed to beat really sucks. It's just way too easy to lure out and beat.
B+ -->
A-
An excellent support Pokemon in general and one of the best Stealth Rock users in the tier right now. This thing is very consistent at what it does and is one of the easiest Pokemon to slap on an offensive team. Has a customizable fourth moveslot that allows it to act as a lure or deal with a specific threat the its team is weak to.
B -->
B-
This thing is a terrible Defog user due to the fact that it loses to every single relevant Stealth Rock user. In fact, I really can't think of a good Stealth Rock user it can even beat. It's not a bad defensive Pokemon, but the fact that it just flat-out fails at executing its main niche warrants this change.
B -->
B+
This on the other hand is an unappreciated Pokemon. It makes for a good Rapid Spin user because it can actually threaten Rhyperior and Mega Steelix. On top of that, it has quite a few defensive merits in being able to beat Swords Dance Mega Abomasnow, Cobalion, and Tyrantrum. Hitmontop is probably the best form of hazard removal for stall teams nowadays so it deserves the bump.
Unranked -->
C+
I was the first person to really diss this Pokemon, but a lot of things have changed to actually make it viable and on the same par if not better than Kricketune. Gaining Knock Off + Sticky Web is a great boon because now it can threaten more defensive Pokemon with the threat of item removal just like Kricketune does. There's also the distinct lack of good Defog users, especially ones that can beat it which makes the Taunt advantage not as huge as it was once before. Leavanny's Speed is also very good for it as it can outspeed lead Qwilfish and set up Sticky Web as opposed to being Taunted and denied of it. Access to Leaf Storm also lets it greatly threaten Rhyperior and forcing lead Cobalion into a 50/50 with Magic Coat is great too! Overall, it deserves to be ranked where Kricketune is at the very least. Ironically, it's probably the better Sticky Web user now.