Good chance to taste an amontillado (NPU, far right), palo cortado (Regente, middle) and oloroso (Don Jose, left). 

The visual impression is as you would expect – progressively deeper  and richer in colour from amontillado to oloroso. 

The noses are text book – the amontillado has more bready nuttiness, the palo cortado a touch of spicey ginger, and the oloroso by comparison has an even richer, old red wine and barrel aroma (to be honest a bit unbalanced and ott). Of the three the most elegant and appetising for me is the amontillado – the palo may be more interesting but I like the balance and umami of the amontillado. 
On the palate there are clear steps up in zing, acidity, and structure. Here the little bit of spice in the palo cortado gives it a nice added dimension, whereas the oloroso for me seems more intense but less defined – maybe that same bit of imbalance flavourwise.

Three nice bottles that seem great examples of their styles. All really drinkable too.