I can only speak from experience when it comes to Korkers. I've owned 2 pairs of Korkers over the last 10 years. I can testify to the fact that are very well made and comfortable. Their customer service is excellent as well. I fish pretty hard and my current pair of Korkers still look new, after 4 years.
Simms G4's are a great boot. Wore them everyday for 120 days in the field this summer and they look good still. Sole is worn, but thats a good amount of time on a pair of boots. I have seen the new korkers and there wouldn't be much left of them after that kind of beating. Buddy had a pair start blowing up after 2 weeks.
I've had great luck with the Korkers and I do like being able to add or remove stud soles, rubber, etc. at times. You can still get a version with laces if you don't like the BOA system. I've had no problems with the BOA and like it.
I don't know much about the Korkers Chromes other than a buddy of mine said after a month of fishing the inner changeable soles quit sticking.............. but I can tell you the SIMMS G4 boot is a fricken clod-hopper! HUGE and heavy! Next time you're in a shop- hold the bottoms together of a G4 boot and any
other Simms boot like the Rivershed, Guide Boot, BOA, etc. A size 10 G4 is bigger than a size 12 of any other boot. I sold mine after once season of wear.
They served their purpose, were comfortable, etc............... but it felt like I was wearing scuba fins with downrigger balls on them! They also fade out super
quick! Hell no to the G4! Just my opinion. If you can take them back............ I would seriously consider the SIMMS Rivershed or BOA boot. Very comfy, fitting, athletic and light!
Korkers has a solid following but I am sold on Simms boots. The ability to change soles, while somewhat appealing is just one more thing that will break. I am hard on boots and fished the heck out of the Generation 1 Riversheds. They are still in working order but I've retired them for the latest version. Comfortable, don't hold as much water weight as some boots do and rock solid. You may want to look at the Guide series or even the Freestones. Those things are bombproof. Simms also has a BOA system if you want that. I prefer laces. The star cleats give me superb traction. Expensive but worth it. Then again there are three contact points per stud.
I have heard first hand and also read people having problems with the Chromes. If you go korkers, check out the latest iteration, apparently this has been addressed. With that said, people say Korkers has great customer service and will take care of you. Then again so Simms will too.