I'd rather start as a a vampire spawn/half-vampire than become one in game, mainly because I can create the character to suit the image rather than have (for example) my gruff dwarven fighter suddenly take on the personality of a cynical witty courtier (which is how I usually see vampires being - living that long must really jade them).
The vampire-spawn as portrayed by Astarion is great, but I'd like to have the option of a female version, a wizard version, cleric version and so on. All with great clothes, of course (Larian, you are working on better cosmtetic options, aren't you?), because no vampire-spawn wizard is going to wear a robe that looks more suited to gardening than promenading through the Underdark. I am now visualising Cat from Red Dwarf (UK comedy sci-fi TV series for those who don't know).
In addition, it would be a firm reason for having been taken by the mind-flayers in the first place. Never mind aliens abducting US backwater hicks to do terrible things to their rear ends, this would be mind-flayers deliberately turning vampire spawn into mind-flayers so see what happens. All PC adventurers are special, but some are more special than others.
