Here's my $0.02 (from sunny Palm Harbor, FL!!!!
Ants is way easier to potentially onsight than the Spring. Pumpy vs. technical, and gear every 3", not every 3' (that's only above the crux when it gets "runout"
like that). There's no chance of getting suckered off line, and every piece of gear is as good as can be gotten w/ trad gear.
Boldville is fun, but awkward, I wouldn't wanna do that to break into 8's. That's what Snooky's and Arrow and Hyjecks are for.
(but NOT Annie Oh)
My first 8 was p1 of SoEO, so that's another contender for every category from Breaking In to Must Do to Classic.
Agreed big-time w/ Nerdom that Casablanca is the 5.8 testpiece (assuming we're calling Modern Times a 9, otherwise MT gets the nod, a no-brainer).
Hard to protect the crux (well), and reachy and pumpy, I had to use a heel-hook, just like on all the other 8's. NOT.
I think Roseland is pretty straighforward for breaking into 9's, it was one of my early 9 onsights, you can TR yerself up the corner until the very top.
Strangely enuff, I had an easier time (mentally - go figger) w/ the moves on WASP vs Sente, and they are 9 and 9- respectively. And PG vs SPORT.
Julie was kind enuff to share my WASP stupidity of climbing thru the crux, only to pro the sh!t out of the 5.4 roof that followed it (since I was thinking: damn, if this is hard and balancy now, and it ain't the even crux yet, then I'm really in for it when I get there!
As for sometimes having an easier time leading something (even onsighting it) vs. following, I've had that happen numerous times.
I often find myself saying "I can't believe I led this" when I go back to stuff I'd led prior.
A course, other times ya hike 'em too.
Apoplexy was a tough onsite for me, and I was climbing well and had done a bunch of other 9's, so I hafta disagree with whomever says it is one for breaking into 9's. At least for me.
It'd be pretty easy to f' up around the flexy flake and become a member of Team AHHHH Ker-Splat, so I'd save that for more of a 'getting comfy at 9' or perhaps even kinda a testpiece.
I'm with the contingent that likes to break into a grade by onsighting something. (or at least attempting to).
NOT that there's anything wrong with any other way of doing so.
Whatever works for you, and gets you up the rock, and keeps yer ass offa the deck, it's all good.