DA: Flex XC 3401, it's lightweight with temp monitoring and pad wear stop feature. good for a beginner to teach you the fundamentals of polishing lightweight until you develop muscle strength and technique.
Rotary: FLEX L3403 VRG Lightweight Circular Polisher, pretty much the same as the 3401, but even lighter and it's a rotary. 4.3lbs with a rotary, hard to lose control and let it sit for a second and burn/swirl the finish.
Honestly it's all personal preferance. Starting out lightweight is not the route I started at, but it's more of a safety precaution for beginners. Once you learn to handle those, it all just falls into place. With most of the brands on this site, you can't go wrong. Unless you're only doing used cars all the time, I'd go with one of the recomended above. However, if you're doing dealer work and getting 20 year old cars that need multi step coats (clay, polish, synthetic, finish wax) and a higher cutting pad with higher speeds to get rid of swirls and cobwebs, I'd go with something more powerful. :xyxthumbs:
If you're really that worried about what you get, go to a junk yard with a sawzaw, start disconnecting battery cables and bring a pickup. Take a few doors and hood/trunk lids off cars as test subjects, it also allows you to see results of every different product. Honestly where I live, I can pay $50 and bring my own tools and carry about 500lbs worth of car parts away before they ask for more money :dblthumb2: Heck of a deal and a perfect way to learn. Be sure to get acrylic, enamel and lacquer type finishes. Don't just go with new wrecked car panels, diversify. Good luck!