Auto vs. Manual, like everything with vaping, is very subjective.
I can't do manuals. I tried, for several months, and still smoked while using them. manuals just don't give me the satisfaction that I derive from an auto. With a manual, beyond the act of pressing a button (which I never liked), there is nearly no lung function. I would constantly hit the cutoff on my manuals because I wasn't exercising my lungs like I would smoking, or with a good auto. With my autos, I almost never hit the cutoff. I've given or traded away all of my manuals and now I'm full auto.
The Volt autos are very good, but since they are "sealed" they have a noticeably stiffer draw. I have both "sealed" and regulated batteries, and unsealed and unregulated batteries. With my "sealed" batteries, I puff on them much like one would with a cigar or a pipe; 2-3 short puffs and then one long, slow draw. Volt autos, especially the X2's, are perfect for this. With the unsealed batteries, I draw on them exactly like a cigarette; fast and hard puffs, usually very short. With the "sealed" batteries, this will quickly kill your lungs; with the unsealed, this is the perfect way to get your "smoke break".
Manuals have their place, and their fans, but it is a very different experience from an auto. For myself at least. Dipping and dripping on my super mini auto is the only thing in 6+ moths to keep me completely away from cigarettes.
For reference, I'm in my early 30's and despite smoking for 15 years I never had any major health or breathing problems related to smoking. I imagine if your lungs have been severely weakened from smoking, a manual is the better option. If not, then you may require that lung hit that an auto can give and a manual can't.