A bit late, but today I tried their 10 year old Tawny Port.
It was brought into Lidl for Christmas, and they had loads of 750ml bottles for £9.99, but I never bothered until now, and they only have a few bottles left.
It's definitely nicer than their usual ruby port for £6.25, though it's more 'different' than 'nicer'. Their normal port is good enough for the price, just sugary sweet (Aldi's is 'honey' sweet), but the 10 year old one tastes like liquid raisins or sultanas. Definitely worth £10 because it tastes naturally sweet, not chemically or artificially sweet. It's no substitute for normal red wine because of the intense sweetness, but as a port it's fantastic for £9.99. It's kind of like how I remember Emva cream as a kid, but with this big 'raisin' after taste.
After shopping in them both for a few years, I've come to the conclusion that Aldi is better for cheap wine, and Lidl is better for their premium wines. A £3.50 bottle in Aldi is palatable whereas there isn't a £4 bottle in Lidl worth buying twice. But the Châteauneuf du Pape in Lidl for £12.49 (I got it for £10.49 at Christmas) is miles better than the £10 bottles in Aldi.
Unrelated, but baking power and sodium bicarbonate is the same in Aldi and Lidl, but the lids on the Lidl tubes are a lot easier to open.
This week, Lidl are doing 1L bottles of olive oil for £3. It doesn't taste as nice as Aldi's 'Specially Selected' olive oil, but for basic things like coating pasta after it's boiled & drained, or frying bacon and eggs, it's a bargain.