Get yourself a 2 or 3 speed manual winch and you will be set for many years to come. 

We took 2 big boats to Exmouth many years ago, 1 with a manual winch, the other with electric. The electric one crapped itself within 2 days and luckily we had an old spare manual one with us.

the time to retrieve with a manual is also twice as quick as what it is with an electric

totally agree with scano.   Stick with a manual 3 speed, it's easier than u think to retrieve a good size boat.. Much cheaper and more reliable. 

I used a fly wheel and a starter motor out of an old ford falcon. Put the fly wheel onto the winch drum shaft made a bracket for the starter motor so that the gears engage when the motor is energised. From hook up to stop takes 17 seconds for a 6m quinine. It might not look as flash as new enclosed winch but hey gets my boat out very quick from any ramp I've come across.

Has been in use for 5 and a bit years and never let me down.
Total cost, a slab of mid strength.

 Its the 712A model suitable for boats 5-7 metres and up to 3400Kgs. The winch was only used a few times during my shoulder operation recuperation. Took it off when I sold my boat. Retail at Whitworths at present is $599. you can have it for $300. I'm SOR.

I used to think only wankers had an electric winch and now I've had mine (Superwinch) for 7 years I can attest that this is still true! Noisey, slow and always takes a bit of fiddling to get contact on the Anderson plugs.

Really handy though when there isn't enough water to drive the boat on and with mine weighing in at just over 3 tons, a shitload less effort.

Daisy

I have a power winch on the cruisecraft,,, slower than mark hutchings running away from cyrol rioli on the wing,, but it gets the boat on the trailer with zero effort every time.

if your not in a hurry electric (good brand) are good.

 I have got a home made electric made from a VP commodore starter motor driving a 300mm pulley. It has been on 3 boats over 15 or more years and it drags a 6m glass boat

in no time.I get lots of comments on how quick it is. If you reckon manual is better go for it.In that time it has failed once and was just a connection that had corroded and fixed in 5 minutes

I have an electric winch on my Caribbean Belmont and it has made solo retrieves so simple. I have the switch on about a 6 mt lead so I can attach the cable and then guide the boat onto the trailer if needed.It is not fast but probably faster than me on the manual winch. If this one breaks I will buy another, had it about 3 years so far.