I'm kind of the wrong person to ask because I'm practically violently anti-conical but I'll calm down my rhetoric on them...
My own, personaly opinion is... conicals are super pretty and have enormous, "wow that is super cool" power but... for homebrewers, the benefits of using them don't come close to justifying the cost. Unless you're something like 60+ gallons at a time, personally, I don't see any reason to use a conical.
You said it yourself... you can get 8 carboys (and you can get a lot more than that for the cost of a conical) so you can have at least 10 beers going at once... or one... in a conical... that'll make yeast harvesting "easier" (easier than simply tipping a carboy upside down)... for a lot more money.
My own personal advice... buy a pile of carboys and a bunch of other equip first and then, if you want to add to the bling and have the money to spare, by all means... go conical.
(and I was writing this as that last post was put up so... any reference was 100% unintentional)