At the moment I have four bottles of lowland scotch open, more than any other region. In spring and summer I love a lowland malt. My recommendations on good lowlanders are Rosebank and Bladnoch. Notes follow:
Perhaps my bottle is now just old and stale but Glenkinchie 10yo is not one of my favorites -- I seem to remember enjoying it more when it was fresh so I may want to crack open my miniature for a comparison. Doesn't seem like a real lowlander to me and never really did, with a hint of smoke in the nose and no true citrousy or grassy notes; in many ways it is more of a light highlander except for the dry finish.
Auchentoshan is the first lowland I ever tried and I didn't like it (thought it was too weak and thin, couldn't appreciate it at the time) so for years I avoided it but I think I need to give it another chance. Only problem is I've been avoiding Morrison Bowmore bottlings recently after getting a bad Bowmore. I wonder if the Auchentoshans have the same problem as some of the Bowmores and Glen Gariochs?
Rosebank is one of my favorites. Murray & McDavid 1989 11yo and Signatory 1990 bourbon cask are both excellent. The Signatory 1991 11yo I have open right now is OK but not as good as the others I mentioned, just not as lively or well balanced. Good Rosebanks generally give me a nose of lemon grass, green apples and malt, with a medium spicy body and a spicy but short, dry and gingery finish.
Bladnoch is another favorite. I've got a 1988 14yo Conn. Choice Gordon & MacPhail bottling open at the moment and it is lovely, wonderful stuff, as good or better than the best Rosebank I've had. The nose is very nice with citrousy, grassy notes along with cereal, malt and even some peat, the body matches well with good mouth feel, cereal, malt and the finish matches again, dry as expected.
Littlemill is one which I've never loved. Strong lemon grass nose, very spirity in both the 1990 Signatory and 8yo OB bottlings I've made notes for. Perhaps there is a great bottling waiting for me -- I've heard that well aged Littlemill bottlings are nice but have yet to sample one.
Never had a St. Maggie or Inverleven. The only Inverleven I've seen for sale here was expensive and not well scored so I didn't pick it up.