one is to build it up with decent part and eventually get a different frame.
the other is build it up cheaply so you can have fun without worrying about getting it nicked/damage/etc. sell it for a reasonable amount, and use that money to fund a new bike.
IMHO, do it the cheap and cheerful way, it's much more fun riding a bike on the cheap than with expensive part.
+1
My current HLE mangaloy was £10, parts = £150