Several years ago, I was wanted to start a recip herd, so I purchased a set of 40 heifer calves from a reputation ranch at a feeder sale. I bred them all as yearlings and then sold 15 off the bottom as bred heifers. I was able to greatly reduce the actual cash I had in these females not considering my feed required to take them through the winter. I am still using several of them and they are now 12 years old. They are Angus and Maine/ Angus cross and they have worked exceptionally well.
I would agree with the comment regarding temperament. Temperament of the recipient, in my opinion, is just as important as their milking ability. There is nothing worse than trying to domesticate a good ET calf that is bonkers simply because the recip was. I cannot stress this enough.
When we were feeding cattle, I had a standing order at a auction barn that had lots of dairies in the area, for Hereford X Holstien or Shorthorn X Holstien heifers. I was able to get about 20 of them and they were about the best recips I ever used. They had great udders, lots of milk, had enough capacity to retain their condition, and they were very quiet. I weaned the calves from them a little early and put them back in the feedlot and finished them, and they all sold as heifers on the rail. I was able to buy them at a substantial discount because they were dairy cross.