REB vs Pyroblast

[Kaiser von Hugal]

Im trying to decide if it makes a difference to main deck one of these over the other.  The wording on REB and Pyroblast are subtley different.  If I have a Lavamancer in play and I want to load my graveyard to activate the 'mancer, can I play either of these cards in response to anything my opponent plays (barring only land of course).  Is the Pyroblast wording different to such a degree that it allows me to play it regardless of whether my opponent plays a blue spell or not?  Is REB's wording sufficiently discreet that it prevents me from playing it if my opponent plays a non-blue spell?

[Jacob Orlove]

You can only play REB on a blue spell or on a blue permanent. This does have one advantage: if you REB a blue permanent and there are no other blue permanents in play, the REB cannot be Misdirected.

Pyroblast, however, can be cast targeting any spell or any permanent. This is useful if you need to feed your graveyard or up the storm count.

[dandan]

Likewise, REB is better if you get Mindslavered as it is harder to 'waste'.

Meddling Mage also comes into the equation occasionally although I've yet to have anyone name REB.

Most people generally regard REB as superior as it does what it does most consistantly than Pyro, with Pro being generally better at doing things not directly related to its main task (such as Storm and graveyard count, crawling out from under a Vise, interaction with Balance, growing a Dryad, targeting skulking dudes, activating Hidden Gibbons, etc).