The real choice isn't 'see a show', it's which kind of night: a big, machine-tooled musical that's run for decades (Les Misérables at the Sondheim, Phantom marking 40 years, The Lion King at the Lyceum) or a sharper, riskier play in a gilded old house. Either way the staging is top-tier — but the venues are Victorian, so legroom and sightlines in the cheap seats can be rough.
Les Misérables (at the Sondheim) has run in London since 1985 — the world's longest-running musical; The Phantom of the Opera marks 40 years in 2026. · en.wikipedia.org
The Lion King, open at the Lyceum since 1999, has extended its run into November 2026 and ranks among the longest-running West End shows. · westendtheatre.com