Standard Ruby Ports are blends from different years. As with Whiskeys without an indication of age, these tend to not really impress as they are the Entry-Level of Ruby Ports.
Late Bottled Vintage Ports (LBV)
Late Bottled Vintage Ports are the Cru Bourgeois class of the Rubies. Wines of a single year are bottled (most are thoroughly filtered when bottled) after 4-6 years of maturation in a big wooden vat. They are produced to be consumed without further bottle ageing. LBVs are perfect every day wines, because they offer enormous complexity but show the unique characteristics of the single harvest. Bottles of LBV port are best finished within two weeks of opening.
LBV Ports are excellent wines for port-beginners because they need to be neither decanted nor finished on the same evening. An LBV wine combines fruitiness and freshness at a moderate price-level. My advice: if you have little or no experience with Port start with a Late Bottled Vintage Port.
Vintage Port is the Field-Marshal in the Port-rankings. These wines are only produced in years with overall excellent conditions, on average three times every decade. There are different declaration (the decision to produce a Vintage Port) policies amongst the producers. Thus you are able to find a Noval Vintage Port 1931, but not one from Niepoort or Taylor made in the same year.
Vintage Ports represent the top percentage of a harvest and are bottled unfiltered after ageing only 2 years in a very big wooden vat. The following bottle-ageing process will take a couple of years and can last decades. Like with a great Bordeaux wine one may only be able to fully encounter its potential if the Vintage Port is given enough time in the bottle. A mature Vintage Port will be the focus of the evening, because you will find complexity and depth in these wines that are very hard to find with non-fortified wines.