1. Did you notice any oxidation flavors in the first two beers? O2 diffusion is my biggest fear.
Nope, not yet at least. It might also be too soon to know. I wouldn't worry about it. I'd suggest you make a batch that will pretty much top off the barrel with 8 gallons of fermented beer. Flush the barrel with CO2 if you can, before you fill it. Commercial brewers are making barrel-aged beers to beat the band these days, and most of them are great.
2. Have you funkified it yet?
Not yet, but I'm thinking the Cherry Wheat that's going in shortly will get funked w/brett. I also have a few gallons that won't fit into the barrel, which I will keg and carb normally.
3. Would you say its worth the investment?
I recognize that lots of what I spend on this hobby falls way outside of the realm of "worth the investment", but rather is spent because I want to, and I can. In the case of this barrel:
- I wanted more bourbon barrel beers of my own, on my schedule rather than brewing with others to fill a large barrel;
- it was relatively affordable (compared with $300-$400 for a new oak barrel);
- it fits on a shelf in my basement;
- the Spousal Unit didn't beat me with a 2x4 because of the barrel;
- the beers are coming out of it mighty good;
- and I will definitely do it again.
So by all of those measures, I guess that's a long way to say yes