Go with a drum roaster. Learning how to roast is not hard, master the art of roasting is a life time of devotion. Go to Ambex or Deidrich's presentation, they will show you the first step, the rest if up to you. If you are worry about lack of experience, you can 1) buy a Hottop drum roaster for home for about $600 and roast at home, sweetmaria.com carries them. 2) you can visit bootcoffee.com, they offer classes that are not designed to sell you a roaster. I have heard nothing but great things about boot, and I plan to take some classes at boot sometime this year. 3) Visit your green beans suppliers, if they are any good, they will cup with you, and maybe they might know if some of their customers who are not your competitors are willing to share their know how with you. Just be careful not to pick up any of their bad habits.
Sivetz has his followers. Some of the best roasters in the country use Sivetz. I don't know anything about it, but if I were to look at drum roast alternative, Sivetz is where I will start.
Automation is not the end all. You will still need to know how you want your coffees to taste and develop YOUR roasting profile for different beans, automation will give you consistency from this point on. However, if profiles you developed brew bad tasting coffee, you will have bad coffee consistently. Also, you cannot develop these profiles just once, you need to constantly check your coffees as beans can be different from bag to bag, not to mention from year to year.
Or you can roast the heck out of your beans like Starbucks, then it doesn't matter what type of roaster you use.