there sint much difference. The Gel nails are more see through and are a little more hardy, its still in powder form like acrylic is and you cant really tell the difference, other than that the GEL is a bit more see through and because of that a bit more pink as you can see your own colour underneath-i also think it can be filed a tiny bit thinner-acrylic can too but gel is less likely to break. only thing with gel is that you can see tiny bubbles where the gel has dried.
neither - both require expensive maintenance and ruin your natural nails. you can tell they are false and i love looking at natural nails...mine are lovely. i bit my nails until i was 27 and now they are my pride and joy - i almost feel bereaved when they break off (which is not often as i look after them pretty well). if you keep natural nails a reasonable length, feed and regulalry file them they can look great - and you can give them a french polish that looks good and still tie shoelaces or pick up coins etc...