Good points....
1, They are amazing at cutting though ANYTHING! Bought at the time for a welsh x who was like a yetti but they were easy. (never once overheating)
2, I've never had them serviced and 5 years on they are still as good as they day i bought them (not recommending you dont look after them properly!)
3, they are seriously cheap
Bad points
1, for me i have no electric so can no longer use mine :-(
2, they would maybe be difficult on nervous horses- they are fairly loud and vibratey
3, they are bigger than some which didnt bother me but might some people.
On the whole if your horse is ok with being clipped i'd certainly buy them!
I bought a set last winter for my very hairy cob and have always worked really well, and as long as the coat is clean, the blades can do several clips (my current set has happily done 5 full clips!!)
The down side is that they are very noisy, vibrate and clumsy, so I have to use trimmers for face, elbows and other knobbly bits.
My 2 are good to clip but would be wary of using them on a nervous horse.
i have some and two years on they are still great, used for clipping shetlands/welsh ponies and can cope with heavy coats no problem. Cheap blade replacement and no overheating.
As said they are quite large so probably better to use smaller ones for tricky spots. Thats the only draw back i can think of.
So in conclusion they're a bit big, loud and vibrate a fair amount. I think we can deal with that (well in theory my horse should be able to, but we'll see )