I find DMC3 to be a terribly tough game and I had to switch difficulty down to easy in order to be able to gain any progress. Still I had a very hard time with the bosses in mission 5 and others later on (I can't imagine how I'd be able to beat the mission 20 boss on DMD without spamming items).

I discovered Devil May Cry back in 2001 because I was a big fan of the Resident Evil series and I liked the theme of the first part as well. Due to the reviews I didn't try DMC2 & 3 on the PS3 but now bought the HD collection. I don't really like the presentation of the story of DMC3 and imo it has nothing of the atmosphere of the first part but I must admit that the fighting system is impressive. Now I was never much into fighting games and I suck hard at Tekken & co.
I find it very difficult to keep a good style up in DMC3 and to decide when to use which weapons best. I finished the game on easy and normal with Dante and am now on hard mode run (somewhere between mission 15 and 18 I think) but I'm using a lot of items and basically speed running through the game wherever I can so I'm hardly motivated to go through very hard as well. After a longer break I started again yesterday with Vergil and decided to do the same roadmap (meaning I level up everything on easy difficulty and afterwards take on normal, hard, very hard and eventually DMD).

It seems easier now but I'm not sure if it's because of Vergil or the experience I got with other games in the meantime. The flying swords do a lot of damage and I can finish boss fights by mostly just avoiding their attacks by jumping and rolling while spamming triangle (flying swords attack). Is that ability any use on harder difficulties or would it take over half an hour or more to finish a boss this way? I also decided for now that the gauntlets are the best weapon for me. They have easy to implement attack schemes and seem to do a lot of damages. Any thoughts on that?
I also realized yesterday that for very hard boss fights I could basically use a golden orb to restore with full energy so with some grinding that means I have basically tripple health for any boss fight that is too difficult otherwise, right?
Do you see any major disadvantages/problems playing with Vergil rather than with Dante?

I'd appreciate any tips (bosses, weapons, general strategies) on hard, very hard and DMD difficulty with Vergil...