I was backpacking with a friend and we stayed at the Lost resort for one night and then decided to head back to Bangkok. Our choice was more related to the whole island rather than only to the lost resort. We checked into the lost resort after Jeps bungalow was fully booked out. Though Jeps bungalow was in the better location on the beach with nice breakfast the owner was terribly unfriendly whereas the lost resort staff was nice, rooms okay.
However, we cannot recommend Ko Samet. After spending time on the islands (Ko Phangang, Ko Tao), Ko Samet is really sad, dirty, unfriendly, barely anybody speaks any words of English and no infrastructure (e.g. hospitals!), unorganized transportation etc. Our experience was so bad that we'd rather go back to Bangkok for 3 nights.