I use the Fieldsheer expander saddle bags and the matching top case on my ZX14. I had Givi 36L sides and a 46L top case on my prior bike (Bandit 1200). My thoughts on Hard bags vs. Soft bags: Hard bags are much easier to pack, they're usually watertight (Givi's were top notch high quality). Hard bags show scratches, scuffs, etc,(if that worries one). They obviously weigh more (empty). And lastly, it takes mounting hardware & brackets. With the proper size hard bags, you can usually pack whatver you want, and not worry at all about your contents while in transit. Soft Bags: Very portable, lighter, a bit of a pain to pack (I put groups of items in large ziplock bags, then pack into the soft bag, this makes it easier to remove contents without everything coming out at once), soft bags are notcompletely weather proof, and they're not as securely attached to the bike. They're easier to access while on the road. I don't worry about scratches and scuffs when I throw them in the corner of a tent/room. For my use, which is about two overnight (1-3 nights)trips per year, the soft bags are a better fit.
On to my review of the Fieldsheer bags in the link above: Plenty of room, good construction on the seams/zippers, material is strong and the pockets are easy to access. The straps provided for fastening the bags to the bike are pretty weak. Mine actually broke the first time I went out. I may have over torqued, but believe that you should have a very secure load when taking off for a 4 day trip. I fixed the straps with epoxy glue, which looks tacky (no pun intended) but works great. The plastic connectors are also a bit undersized, but seem to be holding up. I may attempt to upgrade the fasteners. The matching Fieldsheer top case is very nice. I use it everyday for commuting. The bungie straps have not rubbed any scuffs on the rear cowling. However, one of the plastic connectors that allows attachement to the saddle bags did flop around and added a small scuff to my finish; which I was able to remove with scratch remover.
My 2 cents.