I will only allude to the species I have personally kept. I believe Idolos are beautiful, but I can't speak to their personality.
#1 for me is definitely going to be Shields. They are aggressive with their prey, but absolute darlings to handle. I have yet to tick one off enough to flare up for me, but then, I haven't really tried either! They are also easy to breed...my male has survived breeding both females and is still alive more than two months later. The only bad thing is that the younger Shields seem to be prone to mismolts unless humidity is kept fairly high. They are a thirsty bunch on the same level as the Chinese.
#2 on my favs list is the Violins. While I have yet to behold an adult, I have full confidence that I will still love them then. They are communal, which is a big bonus for me, and they have a very elegant look to them. I consider them the "Executive Desk Pet" of the mantis world, as I could just see the practical CEO of a big corporation with a tank full of Violins, instead of expensive/fragile saltwater fish. I have yet to have one mismolt on me and I have yet to attempt breeding them, but so far, they are just way out cool.
Now, I will give you what I know to be my husband's top two, since I just know him that well:
#1 - Idolomantis Diabolica - It's the "cool" factor. The only "flower" mantis that a manly man should ever consider owning.
He doesn't know much more about them except the molting problem, and he's confident that he can create an ideal setup to prevent that problem.
#2 - Ghosts - Yes, they are small, but they are just too friggin' awesome! He likes that they have that bizarre alien look to them, yet they are as simple as all get-out to care for, breed & hatch a new generation. They'll also eat anything they can grab...awesome!
Honorable mention: Hubby is also enthralled with the idea of getting Megas...though, I'm not sure why, except for the fact that they just seem to be so hard to obtain. (We both have Nordstrom's tastes on a K-mart budget!)
Find a one-of-a-kind muscle car or motorcycle, and he'll probably want that, too! Of course, so would I!