I've had it several times at the White Labs tasting room, which is great because you can get 6-8 beers that are all from the same batch of wort fermented by the pros with different yeasts. WLP099 is consistently subpar when compared to other, better yeasts for the job. At best, the beers it makes are sort of flat and bitter- the worst offenders can have hot alcohol burn or a burnt rubber sort of off flavor I can't identify.
IMO 099 is a bandaid yeast- pretty much only good for fixing mixtakes (underattenuated beers due to underoxygenation, underpitching, or poor temperature control). Almost every strain WL produces should have no problem with a 10% beer and most can do much better than that, particularly if you're treating your yeast well (oxygen, pitching rates, temperature).
So, you've never actually used it yourself??
I used it in a 15.3% target barleywine. I also fermented it cooler than the listed temperature range for the strain. I did consult with White Labs about this before hand to make sure it would work well for this. Since I'm looking at aging it for an extended period (at least 1-3 years) I don't see any issue with it being 'hot'. With fermenting cooler than listed, it should produce much better results. I didn't care about a long fermentation time. It took just about two months to complete fermenting.
Only time will tell how this batch comes out. But, from what the WL person told me, the 'off flavors' you normally get from that strain are due to warmed fermenting temperatures than I used. Most of the time mine was in the 58-61F range (more often in the 58-60F range).
I might try to use WY1728 in another bigger brew. I've already had it go to 12.5% in a batch. I'll be looking to see if I can push it beyond about 14%. From communications I've had with Wyeast lab tech's, it's possible with good O2 infusions, pitching the correct amount of slurry, and giving it a good amount of nutrient.
I always use pure O2 to infuse my wort, and use nutrient in the batches. I used more of both for the barleywine with WLP099, per the documentation available.
BTW, I wouldn't look to use something like WLP099 in anything less than a 14%+ brew. As you mentioned, there are great yeasts available that can hit 10-12% without too much issue. If you're kegging, then you have less to worry about too. Mostly because you don't care if the yeast can bottle carbonate the batch.
Which is the case with my 12.5% wee heavy.
