Reasons to select maps:
Art Style/usability
The Grasslands 1-3 maps are new and have an improved art style like the Desert 1-3 maps that makes it easier to identify light/heavy woods, water, etc. The Dig maps also fit in here with honorable mentions to the Woodlands, River Valley, Wide River, and Battleforce maps.
Scenario Based
Military Base, Seaport, and Drop Port maps are good picks if you want to run published scenarios, since they are in many of them.
Urban maps generally fall in here as well
Reasons to avoid maps:
Poor Art Style
Desert Mountains and Sinkholes, Moonscapes, and Deep Canyons.
Poor Balance
Mountain Lake
PITA to play on Note that these maps can make for interesting use in scenario design, but are not generally fun to play on IMO
Drainage Basins, Heavy Woods, Large Lakes 1, any Canyons
Niche Use
City Skyscraper and Box Canyon (also PITA, YMMV) generally.
The City Grid, CityTech, and City Ruin maps fall here as well since they practically require terrain hexes.
Some maps need larger play areas to be useful, like the Archipelagos, Large Mountains, and Coasts.