RTL-SDR is not for beginners only, it is great cheap every day SDR with known parameters. If you know what you are doing, RTL-SDR solves 90% of your receiving tasks. It is noisy in some frequency range, it has spurious signals, it is only 8 bit, but professionals easily deal with all there things. As you learn more in radio world, RTL-SDR open new opportunities for you and will never die as a receiver. Later you will start writing your software for it to process I/Q samples.