Italy is the blades. I'd probably rank the countries like this as far as my preferences go:
1. France. Easy paths to 18. Complacent German players (i.e. those who view the West as a 2v1 and don't bother to involve Russia and/or Italy) abound, and you are the clearly better ally for Germany and the bigger beneficiary of England's demise, so you end up with a very clear vision for how your game should play out. Naturally strong defenses give you a lot of room for error.
2. Italy. Similar ease to 18 as France, and great allies too (Germany and Russia are phenomenal pairings with Italy). Problem is that most German players don't recognize Italy's potential as an ally, and Russia is intrinsically vulnerable to just getting blown up by AT or EG and leaving you holding the bag of shit against Austria. Italy gets better in games with more skilled players across the board, since those games have fewer runaway blowouts and players with the strategic vision to recognize what Italy has to offer them.
3. Austria. The only problem with this country is that soloing is hard due to its awful naval capabilities. Yeah, you're exposed early, and yeah, Italy can bury you early if they want. This is a net weakness, but it's not that big of one, because it gives you overwhelmingly clear objectives from the start of the game. The gameplan is almost linear: go for Greece, move to Galicia, pacify Italy, secure the Balkans, expand where convenient from there. This is a big strength because you know what you need to be working toward from day 1, which means you have a clearer picture for when things are going wrong and you need to pivot.
4. Russia. Gets the edge over Germany because it has more paths to 18. Russia and Germany are a test of your work ethic. In Russia's case, you are overextended and vulnerable to a concerted attack early in the game, but your overextension gives you a lot of offensive potential and, with that, lots of opportunities to make good alliances. You have two great allies for the long haul in France and Italy, and you aren't an existential threat to any individual power, meaning no one feels they "can't work with you" by default. You have to work HARD to make Russia good, but the explosive potential is there.
5. Germany. Basically a less explosive Russia. Your main problem is that England and France both come out ahead of you in a war against the other one. You have to get Russia or Italy involved in Western affairs to prosper. But Russia makes you walk a tightrope where you get them involved enough to make England collapse, but not so involved that they gain a bunch of centers from their involvement and turn on you next; and Italy so often relegates itself to being an "Eastern" power that it doesn't even see its own potential against France. Again, you gotta work hard with these guys to do well.
6. England. Obvious enough path to 18, and a strong defensive position gives you the strategic edge against everybody around you. You are the presumptive favorite to come out on top of any Western diplomatic scene that doesn't involve a coalition against you. Problem is, everybody knows this, and if people behave accordingly, you're never going to get a chance to flex that muscle. Your saving grace is the fact that people are bad and make all kinds of diplomatic and strategic mistakes, and you only need one thing to go right (France and Germany not allying against you immediately) before you have the ability to brute-force your way to a dominant position.
7. Turkey. Godawful. See everything wrong with England -- neighbors being aware of your inevitability over them, poor paths to 18 -- but then compound it with the fact that Edi Birsan hoodwinked every Italian player forever into thinking that they should default to killing you instead of considering their options, and the fact that surviving the first round of eliminations doesn't actually put you far ahead of your opponents. (Austria is much better at exerting force in the Balkans than Germany or France are in the Lowlands and the other's home territory; Russia can just explode with a good start and outflank you in Austria and the Balkans while running away with centers in Scandinavia and Germany; Italy has a fighting chance at turning you back in the Balkans and stalling the Med on his own; and any combination of those three can still easily beat you back even after you get to 5-6 centers.) Turkey is abysmal to play with no realistic diplomatic options: Austria doesn't want shit to do with you 9 times out of 10, Italy defaults to throwing 75% of his military at you, and Russia doesn't mind working with you necessarily, but is wary of you having any real success and will drop you for Italy in a heartbeat. And even if you DO make it out of the slaughterhouse that is the Balkans, you're still approximately 95 million light years away from the stalemate line, let alone the 18th center you'll have to somehow take on the other side of it. What were they thinking???