so far I have relied on the in-built Voice Memos app for recording and it's not too bad.... however I was wondering if any of you know of any other iPhone apps that can give better results, particularly in terms of sound quality.
Sorry I'm a bit late on this one, but you might want to give fiRe 2 field recorder a shot. It does a ton of stuff, but the important one that I haven't seen anywhere else yet is that it can bypass the processing that iOS applies to recordings by default. Having made a few test recordings, it turns out that the mic in the iPhone is a fair bit more capable than I thought, but being marred by Apple's processing layer. Without it, you'll notice much more low end, less compression hence a lower noise flaw and less hiss. It doesn't have the little EQ bump to emphasize vocals without the iOS processing on, but that's A) a worthy trade off and B) easy to apply later if it turns out that it'll really make a difference to a particular recording. The processing Apple applies makes perfect sense if the sounds coming into that mic were destined for transmission over phone lines, Skype, or other such scenarios, but IMO SSLers would be better off without it.