Le Petit Lion is indeed the ‘designated’ 2nd wine of Las Cases BUT it’s new having been around for less than 10 years whereas Clos du Marquis is a centurion at least IIRC. Of course Bahans de Haut-Brion is now called Le Clarence de Haut-Brion and still designated the second wine.
Prior to Le Petit Lion, Clos du Marquis was usually considered the 2nd wine of the estate even though it was [substantially] from its own separate ‘Clos’ although I recall several times over the years, before Le Petit Lion was created, when parts of the normal cepage of the Grand Vin e.g. the Cabernet Franc were ‘demoted’ to Clos du Marquis - just as today such decisions are presumably what also makes up Le Petit Lion along with parts of the vineyard that would not be used for the Grand Vin for reasons e.g. of vine age.
However one wants to designate it [similar 'arguments could be applied to other famous seconds] IMO Clos du Marquis was always one of the superior wines amongst the top ‘seconds’. Currently happily drinking the 96.
As for the rest the most reliably good and most expensive was, as others have mentioned, Les Forts de Latour although up to 2000 most of the second wines of the premier and deuxieme GCs including Les Forts were reasonable value. Of course since then we have seen insane values for Les Carruades [along with other wines in the Lafite Rothschild Group] while other wines have simply followed the Bordeaux spiral.
The only second I have bought since 2000 was the 2005 Dame de Montrose which, en primeur, was still good value and a very decent wine.
I’ve never found that to be a category worth pursuing - oddly high prices relative to the quality, yet I don’t really perceive much prestige factor to them either.
Clos du Marquis is good - I agree that it’s not really a “second wine” in the normal sense of the term, but I guess people have different opinions about that.
Actually the 3rd label of Latour, Pauillac de Latour, could be very nice too. The '09 vintage is really good but price accordingly, definitely no bargain.
The 2011 Moulins de Citrans is not outstanding. It is not excellent, or even very good. It is good. A discounter here had it for €4,99. At that price it is mighty enjoyable as a daily drinker.
I’ve been very enthused about the 2016 Le Marquis de Calon Segur [St Estephe] 14% abv. Better on day 2, but still darn good popped and poured. Vigorous, masculine (!) flavor depth, elements of oak, and hefty structure especially when cool. Merlot driven, but still a serious wine, and one I would expect to hold well for a decade after the vintage. Just as good as the 2000 La Dame de Montrose was. A- in my ledger.
