There is good shore diving on GC - easy access to sites out West and North. IIRC from your other post, you're coming in to Georgetown for the day, right? So you'll want to stay on the West End and/or up North. One of my favorite easy access shore dives there is Robert's /Turtle Farm Reef up north at the Cracked Conch (Sundivers). Nice mini wall from 20-60' with a deep wall just a few hundred yards offshore. We do this dive every time we're there. There's also nice shore diving up at Cobalt Coast and Lighthouse Point (LHP is on the way to the Turtle Farm -I haven't done LHP myself yet) CC is further up. Back down towards G-Town there's Cemetary, Cheeseburger, Devil's Grotto, Eden Rock, Sunset, and Smith's Cove just to name a few. GC has plenty of nice shore sites - most with dive ops on site to rent tanks from.
As to how they compare to boat dives, well - they're (for the most part) probably not quite as lush as some of the GC (especially East End) boat sites, but are better than many boat sites in other locales.