Hogg was in sensational form for Scotland during the autumn internationals and the RBS 6 Nations and has regularly impressed for his club side throughout the season.
And with the 20-year-old now having been named alongside 2009 Lions Leigh Halfpenny and Rob Kearney as Gatland's chosen No15s, both Gray and Maitland are convinced he will kick on once more on the hard grounds of the southern hemisphere.
"He's 20 years old and he's probably the most exciting player to come out of Scotland," said Maitland, Hogg's back-three colleague with both club and country.
"Scotland probably hasn't seen a player like him for quite a while. He's got a massive career in front of him.
"He's young, he's ambitious and he's got no fear. You see how he carries the ball back and how electric he can be.
"He can definitely be even better in Australia. He's rapid, and if you put him on a hard tack he'll skin people."
Those sentiments are echoed by Sale second row Gray, who played with Hogg at Glasgow last season before swapping the Warriors for the Sharks in the summer.
"He's come on leaps and bounds but I think everybody in Scotland knew his potential," said Gray.
"He's a quality player. He's got bags and bags of pace and he's in great form at the moment."
Conditions in Australia will suit Stuart Hogg according to two men who know him better than most
Hogg isn't the only Scottish Lion in imperious form right now, either, with Maitland also winning plenty of plaudits since his winter switch from New Zealand.
The former Crusaders star helped Glasgow reach the domestic play-offs and has shone in his five starts for Scotland.
Gatland spoke previously about the 24-year-old's positive and professional attitude both on and off the pitch and Gray says that the Lions will soon see just how good a player and a bloke Maitland really is.
"He's certainly made an impression," added Gray.
"He's quick, I can tell you that. He's a really good boy, a great guy off the pitch. On it, he's a superb player - he's pretty classy.
"He's just a down-to-earth, chilled out guy. He's naturally very professional. He takes his rugby very seriously but when you talk to him off the pitch he's very chilled out."