It may be rare, but the overall use of the Tanooki Suit wins out in my book. Then again, the suit is usually given out during the level which it will prove most useful, so...
hussdelrio, will you tell me what the big deal with the tanuki suit is? I always got it, but never used any of its functionality over and above the basic tail-smacking and flying that the ears/tail give you.
But with the hammer suit, you can kill everything! You can destroy the whomps, ghosts, all enemies basically, and you can kill Bowser in a few seconds.
Go through world 6, beat 6-6, get the suit from the hut, and then die until you have to continue. you can pick up from 6-5 and repeat until you have all the suits you want or that fucking turtle in 6-6 drives you to unplug you system thereby undoing all your work.