Best thing I can say about the 704 is that it is a simple, proven design. That is, a few parts and no frills.
I still have a black 704 that I got back in the 80s. I liked it when it worked, but the eccentric and bail springs wound up breaking on it. I remember standing on the beach with my hand gaff wedged between the reel and the sand spike so that the rotor wouldn't turn backwards.
Not that big of a deal, as I just went over to Betty & Nick's to get the parts, but still a pain.
I definitely prefered the original SS (skirted spool) series reels to the 700 series, but I still can't find it in my heart to get rid of it. In fact, while picking up parts for fellinger's reels, I wound up getting some for my 704 (new drag washers, bumper, etc.) to fix her up a bit.