I bought a Spinfisher 10500 and a 50lb Star rod a while back to fish for sharks at Sebastian Inlet. At the time this was only because I needed to be able to 'cast' 20ft to get my bait out into the current. I thought I was taking a big step down from my conventional rig and was risking getting spooled if I hooked into a big one. So far it has worked just fine handling 5-6ft blacktips with ease.
But recently I have been reading up on the specs and reviews of many of the top spinning reels on the market. They are pretty impressive. A rig with 50-60lbs of drag and 400-500yds of 80lb line on a strong rod is a pretty formidable weapon!
I'm curious how many of you use spinning reels to fish for big sharks. What is the biggest you have landed? Have you gotten spooled?
Where I fish in NC the breakers are far out so it is hard to cast far enough to get past the breakers so a kayak is best for me. On a few select days the surf is calm and I cast some baits out but I still haven't had any sharks on casting gear from the beach. However I have been spooled on a Penn Spinfisher 10500 off a pier.
If you are already doing well with your casting setup, then I don't see any need to replace other than just to have a bigger gun handy, or if you start yaking baits out. I use the Lethal 100 along with an Ocean Master 12ft rod for casting bait, a beast of a combo in the spinner line-up, it can pull just about anything in from shore. For myself, I cannot see the need for another setup unless I start yaking baits out. Occasionally, though, the "big ones" do come in close and you will be spooled....that's just shark fishing. Even the biggest baddest reels get smoked sometimes 
We have gotten several lemons on spinning gear. mostly around the 7-8ft range but a couple over 8ft. With the SSV10500 we have never needed more than 300 yards of line. We run 65LB power pro. I got a scalloped hammer that ripped some drag and my buddy got a juvi T head.
Best fight I have seen on that reel was a spotted eagle ray that was at least 60" across.
I have read reports of two bull sharks at 8ft or more that were caught on the ssv10500.
I got a massive goliath grouper on a cabo 80 loaded with 65 power pro. Probably the biggest fish ever landed on surf gear (still researching that one). If there are no rocks to cut you off, you would be surprised at what you can catch.
Sometimes we'll yak baits on the surf gear if we can not cast to the trough, use a longer rig at that point.
Interesting responses. So basically spinning reels aren't just for casting any more:)
It sounds like a heavy duty spinning rig could probably handle a near-monster? 9ft, 10ft, 11ft?
I wonder why more people don't use them even when paddling out baits? Or maybe they do?
A Cabo 120 or big Spheros is half the weight and half the cost of an 80W and even has MORE drag than most. That's what really surprised me.
If it comes down to line capacity then, well, we can always think outside of the box. Fill up the reel and leave another 100+ yds on top. Kayak out the slack and fight the shark from the top of the spool. Just back up the beach to land him.
What do ya'll think? I don't plan on selling any of my conventionals just yet but I'm thinking I might upgrade my SF 10500 to a Cabo 120:)
I got a cabo 120 new in the box, $260 if you want to pick it up in coconut creek, FL.
The drag pressure on the new spinning reels is insane, but overall, the design of the reel is not as strong as a conventional. If you are ever doing battle against a BIG fish on a spinning reel, make sure the line roller is closest to the rod when that fish is running, and do not crank against the fish.
Some beaches have too many rocks and ya gotta fish Mono so ya need the large conventional reels.
I would not suggest over filling the reel. That can only lead to bad things happening. If you want to save cash on a conventional, get the senator!
A lot of people catch big sharks on Spinning Gear, it can be done. Check all line connections, change line if its abraded, make sure the hook is sharp, and get a large sized,high quality spinning reel. The Penn Spinfisher is a good choice.
I have a Fin Nor LT80 that I bought for tarpon that I'm going to put to the test on Anna Maria Island. It's not mounted on the best rod for sharking, but it's formidable. It's on a Shimano Terramar Extra Heavy 8 foot rod rated at 40 to 80lb test. So far I hauled a ray in that was 3.5 feet across and it wasn't much of a fight. I've got 250 yards of 65 lb braid on it and I'm adding a mono topshot of whatever I can fit, up to 100 yards. (Will probably only hold 60 to 70 yards.)
That Fin Nor has 40 lbs of drag and it's built like a tank. The LT100 has 45 lbs and independent tests have shown it to be smooth and perform at at 52 lbs! A spinning reel! That's a pretty stiff reel.
Last year I learned my less about braid and fishing away from your rig. I was hunting tarpon on my paddleboard about 300 yards out. My line was rigged and was sitting another 100 yards from me when some jerk in a boat decides to ride really close to where my line was in his boat. Sure enough my reel starts screaming and so did I. The boat spooled me of course because I couldn't get to my knife for fear of losing my rod or my life. 
He actually started pulling me as the braid wrapped around his prop. I don't know how fast I was going when the braid finally snapped but I paddled back to shore hoping every inch of my braid and hook got wrapped around his prop and bogged down his outboard. 
I got home and broke down the reel expecting something to be broke or worn and that Fin Nor was clean, pristine and I couldn't find ANYTHING worn in any way. Those reels are bulletproof. Bring on the hammers!