There is an article in this months Wine Business Monthly proposing that forest location means nothing to the quality of a barrel and the tightness of grain is the key factor in oak quality. I haven't worked all the way through the article yet but it got me thinking about our oak.
I use Claude Gillet and Sequin Moreau for Chardonnay. The Gillet is very subtle with slight vanilla notes and seems to bring forward pear, and fig fruit. The Sequin Moreau brings smokey notes and seems to get out more pit fruit, peach and pear. I like the combo of using both. I used about 60% new oak this past year, that seems about right. The Chardonnay is very low yield though with good acidity. If I had 'warmer' fruit, I think I'd use less new oak to keep from overwhelming it. As it is now the oak is in the background.
For reds I use Sequin Moreau, all French oak. I don't much care for American oak for the style of wine I make. It adds an overt vanilla bean flavor and an 'ice cream' texture I don't care for. I have a total of 6 bottles of Spanish and Aussie wine in my cellar right now - so maybe not making a wine in that style is more a personal choice than anything else. I don't like to drink it, so I don't make it like that.
I like Sequin Moreau due to it's subtle vanilla flavor and it brings a nice spicy note. The fruit is not as 'pure' in new oak, but it does round out the wine and take some edges off. The tannins are smoother and the fruit usually seems fuller and not as sharp as in old oak. Sequin Moreau is one of the more expensive barrels you can get but I like the balance and subtle flavor it brings.
The percentage of new oak used varies by grape and vineyard. I use no new oak on the Haut Tubee most years, and up to 75% new on the Chaine d'Or Cab. It just depends on the wine, vineyard, grape and vintage on how it's going to handle new oak. The Chaine d'Or seems to suck it up and beg for more. After 5-6 months in new oak it's hard to pick out any 'oaky' flavors. The wine just seems smoother and rounder than old oak versions but no overt oak flavors. On a wine like that I'll use more new oak.
I think you do need pretty intense fruit, to use a lot of new oak and not overwhelm a wine in oak flavors. I think of it like salt and pepper. You add a little of each to bring out the flavors of a dish, but too little or too much and you either fail to highlight the flavors or dominate the wine with them. You also have to be aware of what the wine needs. The Eaglepoint Syrah is pretty intense fruit, but Syrah seems to get too smokey and sweet with a lot of new oak. I usually use 20-30% new on Syrah.
Sequin Moreau has never sold oak based on forest location, it's always been about grain tightness, so I guess I'd say I agree with the article. We've tried other barrels, and tasted wines from different producers using different treatments. This seems to be what works best for us. I experiment from time to time, and usually try at least one new thing each year, but in general I'm happy with the oak treatments we're doing now.