Manufacturer: Cobra (I have owned one)
Cost: ~$445
Seller: Cobra (unsure if anyone is still selling in the US)
Weight: 13.2 lbs / 6.0 kg
Construction: Aluminum and fiberglass.
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Pros: Lightest. Least expensive (from $250 to $404 less).
Middle Ground: Thinner padding. Secure steel wing latching mechanism. Pneumatic mid-sized tire. Collapses easily.
Cons: Non-castering tire which can "scrub" on pavement if not attached snuggly, and inline, with the wing - potential to cause damage to the wing. Need to add extra weight to prevent wind guests allowing the wing to rise (I saw this happen at an event which caused the opposite wing to hit a runway light which swung the tail around and swung into the tow vehicle which broke the horizontal and vertical stabilizers).
IMHO: Weak fiberglass cradle (broke mine - had to be repaired and reinforced).
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Manufacturer: SoaringXX (Friend owns one)
Cost: ~$700
Sellers: Craggy Aero and Cumulus Soaring
Construction: Aluminum and fiberglass
Weight: 26.5 lbs / 12.0 kg
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Pros: Casters. Smallest collapsed size. Thickest padding.
Middle Ground: Cannot lock caster. Small solid tire. Non-metallic wing latching mechanism. Suspension.
Cons: Heaviest. Cost. No suspension.
IMHO: I have no direct experience with this newest wing wheel.
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Manufacturer: IMI (I own one now)
Cost: ~$849
Seller: Wings and Wheels
Construction: Steel, aluminum and fiberglass
Weight: 24.3 lbs / 11.0 kg (I weighed mine)
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Pros: Castering locks/unlocks. Secure metallic wing locking mechanism. Suspension.
Middle Ground: Thinner padding. Uses heavy (but strong) steel components. Castering locking mechanism can be "fiddly". Pneumatic mid-sized tire. Collapses easily.
Cons: Costliest. Heavy.
IMHO: Why would you lock it during use? Cumbersome to drag around the flight line when uncollapsed, and castering - I helped this issue by adding two simple "modifications"*.
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*Modifications to my IMI Wing Wheel ...
1) Carry handle (inexpensive Kayak) attached to the upper steel bar.