The "classic" notes below refer to the drink used in a 1:3 ratio with sparkling lemonade and ice, but no garnishes.
Appearance (neat): Bronzed orange-red. Something like the colour of oloroso sherry.
Appearance (classic): Pale orange-amber, not unlike the colour of lager, but a little more orange.
Aroma (neat): Citrus peel, berries, cherries, a waft of cinnamon.
Aroma (classic): Very little. When chilled and diluted it loses presence, but you can still sense a mélange of citrus and faint spices on the nose.
Flavour (neat): Citrus peel, a sweet and mild profile with very laid-back herbal and spice notes. There is a gentle bitter tang in the back of the palate that just suggests gin. Altogether it's very much like a diluted amaro. You *could* drink it neat, but it's meant to be the base for a "cup" [punch] and so is specifically designed for dilution. Drinking it neat would be like drinking orgeat or grenadine neat - you could do it, but ... why?
Flavour (classico): Finally - the crux of the matter. Fruity and sweet with citrus and cherry flavours just detectable. Maybe a pineapple note? A flutter of its gin heritage is just faintly noticeable. Sweet, but not overly so, and palate-cleansing.
Pimm's No.1 is a classic fruit punch base intended as the foundation for long refreshing low-alcohol drinks on a warm afternoon. Whatever mixer you choose (lemonade, ginger ale, soda water, ginger beer, etc.) will stand out, but in the background there always remains a foundation of citrus, delicate spices and herbs.
From the starting point of the "classic" sparkling lemonade dilution, the only limitation on how to use Pimm's is you own imagination. It will combine well with almost anything except dairy products, and has a natural affinity for anything else that contains citrus or some other tart or sour notes. Ginger beer and a dash of grenadine works very well and you can go crazy with garnishes.
I call my own preferred way to take it a "Pimm's Ricky" (although there is no bourbon). I use the classic 1:3 dilution ratio but employ Riccadonna instead of soft-drink. Riccadonna is an inexpensive, low-alcohol (7%) sweet Asti spumante and it works spectacularly well with Pimm's No. 1.
Some folk say that the only way to take Pimm's is with champagne (a "Pimm's and Bolly") but I've always thought champagne is too dry to pair well with it. Spumante or a sweet prosecco works better.
Great stuff, well worth the money. You will be amazed how quickly you will go through a bottle of this.
"Good" : 84/100 (3.75 stars)
By the way,
@Distiller - this product listing should be moved to the "Other" category, now that it exists. Pimm's is not a liqueur by any stretch of the imagination.