Yes, I can tell the difference. To me, clitoral orgasms feel more like electricity. Short and quick, but intense. I can achieve them very quickly, usually in under two minutes with the right level of vibrations if I'm in the mood. Sometimes it takes longer if I wasn't really all that horny to begin with. G spot orgasms are a bit more like an ejaculation of sorts. It feels like the orgasm shoots out from me and comes more like a rolling feeling with a bit of pressure. So instead of being short in length, it takes a while to get there and builds up slowly. It usually takes me quite a bit of time to achieve a G spot orgasm, but they're very intense when I can get them. It takes very specific curves and levels of firmness for me to have one.
I wouldn't say one is better than the other, just that they're different. The G spot orgasm is more intense, but that doesn't really make it any better. Sometimes a larger amount of clitoral orgasms will satisfy me more than a smaller amount of G spot orgasms and vice versa. It just sort of depends on what I'm in the mood for that day.
For what it's worth, even though you didn't ask, I also have regular vaginal orgasms. These are more like waves. They're similar to the G spot in that they build, but they don't come with the ejaculation feeling or pressure that the G spot orgasm does. It's mostly just the sort of wave feeling. These are equally as good as the other two, just depends on my mood.