between your two choices i would say play them both first. then decide. but as for my opinions on 5's for that price range...
i have a friend with an EDB600, four string version, so i cant comment on the B string. it does however sound great. it had a very deep midrangey tone that was great for the stuff he played (led zeppelin, pearl jam covers) i didnt like the playability much though, i thought the neck was too thick. electronics are very nice though in my opinion, and they are a steal. touch as nails too. that thing has taken a helluva beating with not a single mechanical or electronic failure. looks great too.
as for the soundgears, i have an SR800A. i found my soundgear to play nicer than my friends ergo. however thats just my opinion. it has a very fast neck, and was wonderful for slapping. that was its strong point. however, the neck was so thin it was relatively unstable in michigan weather conditions. the eq was better than the ergo, it has a sweepable mid control. at times though it just got in the way. its a great bass in my opinion, but it was also made about 5 years ago, and it sounds as if people dont like the current soundgear line. i have a feeling though that these people have played a lot of lower end soundgears, like the GSR series, or the SR300dx... oh well. opinions are oninions.. these are just mine.
someone else mentioned other basses. in your price range i would defenitly check out a carvin. i have a carvin fretless five and i love it. its got almost every upgrade option possible. cost me about 1100 dollars to the door, and i have yet to play an instrument i liked better. (yes ive played MIA's, warwicks, yamahas etc)
if you can find one i would also check out an ibanez ATK. i have a usa 5 string, and its great. touch as hell, and has a huge fat soud, especially great when slapped. the electronics are first rate with the triple coil humbucker and the 3 band active eq. nice big bridge too. great bass. i would compare it to a stingray, although it is no stingray. i have heard wonderful things about BTB's, although i have never played one in a gig situation. just messed around in stores. they are very well built, and can be best destribed as tight and deep.
another brand i would reccomend is yamaha. i almost bought a BB5GS as my fretted 5, but i came across the ATK. the yamaha is a great bass, very well built, and i liked the sound a lot. the neck was wide and flat too, which i prefer.
last but certianly not least is the MTD kingston. never played one, but ive heard great things. they do however, have passive electronics, and while active electronics would be fairly easy to add (theres extra room in the control cavity) you might as well buy active if thats what you want. i have heard they sound more like a P bass than a stingray, if youre after that bright funky tone you might wanna steer clear. but they are certainly a bargain at under 500 new.
all in all id say you have a lot of options at your price point. if i could choose any of them at teh 700 dollar range, i would defenitly go carvin, even if they arent the pimped out models. the construction is first rate, and i love the playabiity and sound. i would not reccoment fender, but i may be considered odd by many. if you are set on ibanez, thats cool too, as i love their instruments, and i think they are a bargain. if you are set between the ergo and the soundgear, id say it depends on what kind of music you will be using them for. if youll be slapping, or playing anything that requires fast fingering, id say go with the soundgear. if you are going to be playing more groove orientated low end rumbly stuff, or just good old rock and roll, id say go with the ergodyne. its heavier, and sounds like it.
im sorry if i ranted too much, but i hope i was of some help to you. good luck, and let us know what route you go as well as how pleased you are with it!
~Scott