It is vital here to distinguish form the start according to music style: solo jazz or pop artists can achieve good results with a dynamic mic, while classical music solo artists practically always use a mic set up at a distance of one to two metres, which means that dynamic mics are out of the question. In this case you should go for the microphones discussed in single mic recording. Please be mindful of the fact that voices can possess greater acoustic pressure than most instruments!
For ensembles of fewer than ten members (eg barber shop), single microphone recording is still an option, directed towards the different sections, with two or three singers per section sharing a single mic. Other groups should best be recorded using the main mic procedure described elsewhere.
A word on children's choirs: thanks to my several years of work as a bass player in concerts with children's choirs I know that herding cats is child's play compared to getting a large group of children to be still for an extended period of time. Good instincts for working with children and a minder to assist you are vital if you wish to succeed. Don't be discouraged: recording work with children requires patience, empathy and time limits, since children's concentration tends to wane rather quickly. In my experience, two hours are the absolute longest time you can profitably use ("Ok, kids, five more minutes of concentration and then you'll get your ice creams...").