my ID does well on blue chip (lami light) but if you need gain a bit of weight sumo is good about £15 a bag i used to use it on a tb that came to me for a bit of weight gain.
Used both for about 6 months to see what happened, Top Spec won hands down, his coat is amazing and hoofs are fab! (And its a bit cheaper too, well worth a try.
Top Spec, definitely. Moved onto this from Blue Chip in the summer and most impressed with results. Only animals that have turned their noses up at it are the dog and cats (who used to go mad for Blue Chip when I was making up feeds!).