I nearly bought the Twinpower SW, luckily read this and have now gone with Stella.
Im sure the twinpower is fantastic, but with the current prices there is no reason for me to buy one. I got a Stella SW5k brand new for AU$650 delivered from the US&A. Baiscally the key features of the stella that sold me were the hybrid anti reverse, the cold forged/brass coated main gear, the awesome waterproofing and the drag. the twinpower has none of the first one, half the second item , less thorough waterproofing but does have the dame drag.
Alan Hawks Views:
There is a world of difference between TPSW and STLSW
1) The gearing of the STL is a cold forged drive gear with bronze surface treatment and a hardened stainless steel pinion. TP has the same drive gear but without the surface treatment, and a brass pinion.
2) Stella's gearing and internal parts and rotor are fitted to the main body that has the reel's stem as an integral part (12383). then the side cover is is screwed on. On TP, the parts and rotor are attached to a gear box (13327) that is separate from the part that carries the reel's stem (13313), before they are screwed together. Needless to say that the Stella's design is way stronger and more reliable.
3) The missing bearing in the nut of the TP is responsible for the floating shaft, which is a feature reducing friction between the rotor and the shaft. It means nothing when you are winding the handle freely, but when you reel under load the difference is obvious in more torque and smoother action in case of the STL.
4) The line roller of the STL has a unique anti-scratch black coating that the TP lacks.
5) The anti-reverse clutch of the TP is the old style used in 1998 Stella F. The one in the STL is far superior.
6) In STL, the screw in cap (12355) provides better protection against water and an added lock to keep the pinion assembly in place if a massive pull was delivered to the rotor. In TP the whole assembly is held only by three screws.