Its been a while since I used GL's but from what I recall, theyre not stelllar at killing anything spesific, but rather generally effective against 3/4 of the ships in the game instead. This would make them seem lackluster against everything, as there is only one tiny group of ships they curbstomp. (Tele raiders, and a few of the swarm ships due to their microscopic health)
Havent used em in a while tho so I might need to see myself.