The blue-throated conure is a member of the "Pyrrhura" species while suns are members of the "aratinga" species. Aside from that and the size and coloring- there aren't any other real 'scientific' differences.
The pyrrhura species are known to be much lower volume. They can be just as noisy as aratingas, but have a lower pitch. Suns have an ear-piercing pitch that is common with aratingas.
All conures are 'clowns', some may be more so than others. What I'd recommend is doing some research on their dispositions and what better suits your likeness.
But if you have already fallen in love with the blue throat, I suppose thats your answer. I wasn't even in the market for a new bird when I got Skittles. I didn't really have choice in the matter. He stole my credit card, bought himself and then snuck off from the pet store and showed up at my door and wouldn't let me leave til I let him in. Now, he runs the place and I just pay rent.