When i Buy a Gladiator i usually wait for the gold cost. 1040 /1080 none premium Gladiators are usually able to hit 80 to 90 in all stats (once upgraded) and a good size of 70+

Don't think i have had a premium Gladiator before but i know if i did i would make sure it come around the cost of 1180 / 1200 at least. (that's my advice)