I take piracetam/pramiracetam/noopept on and off and cycle between caffeine+l-theanine and nicotine. Some non-nootropic supplements I take are fish oil, Vitamin D3, and melatonin. Here are some of my anecdotes.

::Piracetam

I haven't been able to get very consistent results with piracetam, but it's definitely not placebo. I've found that piracetam is hit-or-miss for a lot of people. Some are very sensitive and only need 500mg, while others, like myself, need somewhere around 10g, and it just doesn't work for others. When I started, the effects were fantastic: I had increased focus, more vivid dreams, and was more outgoing and personable when I'm normally introverted. However, after about 2 weeks of regular usage, much of the effect went away. This seems consistent with some other peoples' experiences with piracetam on the web. It seems to be having more effect now after a 2 month break, so it may just be tolerance. Also, @StevePerkins implied that piracetam is illegal to purchase in the US, but it is still unscheduled and legal to buy in most countries.

::Pramiracetam/Noopept

These are much less subtle than piracetam.

I usually take between 200-500mg pramiracetam and it has the same focusing effect of piracetam, but with a stimulating effect as well. I haven't noticed any tolerance issues, even with a period of regular use.

With noopept, I only felt any effects when consuming around 5mg sublingually. It's not a racetam so it's a bit riskier, in my opinion. I felt focused without any stimulating effects and I found it helpful for exams. Some people have reported short term memory issues with higher doses.

::Caffeine/L-theanine

This really is one of the best nootropics around if you can reduce your tolerance. Just caffeine makes me feel jittery, but taking it 1:1 with l-theanine makes me feel calm, focused, and energetic.

::Nicotine

I cycle this with caffeine to reduce tolerance. I use 2mg gums, and it works pretty well. It feels like caffeine with the edge taken off.

Like others have said, the benefits of nootropics are marginal compared to the low hanging fruit of sleep, exercise, and diet. If you're interested, just do your homework beforehand and balance the risks with the benefits. Everybody's different; find out which ones work and don't work for you, at what dosages. I think the racetams are relatively less risky, but they are psychoactive at high dosages, and there have not been studies on their long term effects over several years.