The carriers that are good to shop from are Principal, Ameritas, Guardian, Mass, Standard, and Ohio. Speaking to your question of Ameritas, they are a great company, about $20 billion in size, A+ rated and were formed in 1867 so you should be in good shape. As for riders, that depends on what you want out of a carrier, I typically just have the Own Specialty definition (not to be confused with transitional definitions, Medical Occupation definitions, or Own Occ Not Engaged definitions), residual, and sometimes Future Purchase Options, not personally a fan of COLA as it takes about 10 years on claim for a break even of cumulative payments but that is different post. As for the cost it all depends on your age, gender, medical specialty, state you live in, and the discounts you are entitled to from the broker you are working with.