I bought a bunch of stuff from Korbanth on eBay. I think I ended up spending about $1000... all wasted. It ended up not being to my standards. And that was for helmet, armor, jet pack, knee pads, and gauntlets. So no soft parts. For the money it was better than a Ruby's kit, but certainly not 501'st approvable. I repurposed the armor, but still have the helmet, jet pack, gauntlets, and knee pads. I actually stripped the paint off of the knee pads and pulled the darts off because the scale was wrong. At some point, I plan to sell those items.
This forum is dominated by people who want a screen accurate costume. A lot of the compromises people make here are found part vs. resin cast part. Or real metal part versus cast part. I started out with your mentality thinking I could spend $1,500 on a good costume. I stayed here and became anal retentive and ended up with a great costume, but it was a lot of work and cost a lot of money. The moment I knew I went over the deep end was when I spent the money on real dental files. That was the beginning of the end.
For $600-$700, you can make a lot of compromises to get where you are going, but you can't spend $600-$700 AND have someone else do the work. For that, I think a Ruby's costume is probably your best bet. And it won't be thrilling to Fett heads, but it might be "good enough" for your purposes.
It goes like this:
Rubie's Supreme Edition: $700
korbanth / Sith Planet $1,200 - $1,500
Self made costume $3,000+ a ton of work
Korbanth might sound like a nice compromise, but I bought from him and ended up trashing all of his stuff and starting over because once you get over the $1K hump, your expectations go up markedly. He didn't misrepresent what he was selling (apart from saying it was 501st approvable), it was just not up to standards. I couldn't see it when I was buying because I didn't know what to look for. Confronted with your choice, I would 1) go Rubie's Supreme Edition, 2) go down the path of an accurate suit, or 3) choose something else. If this is not the hardest Star Wars costume to attempt, it is certainly one of the hardest. It can't be done cheaply or without a lot of work.