Consider the following criteria, in order of importance: safety, precision, resolution and features.
1) If you're going to troubleshoot valve circuits, you need a meter with a CAT-II (or better) rating. Branded meters tend to use HRC fuses, which are safer than glass fuses. Accidents happen and I cannot stress the importance of safety. Branded meters also incorporate other safety features like proper board layout, spark gaps, metal oxide varistors and so on.
2) Almost all meters are accurate enough for DIY work but may not be precise. The good ones have higher precision. For someone working with amplifiers, this is especially important because when you, say, adjust DC offset, you will be measuring millivolts with each measurement spaced many minutes apart. The resistor networks in good meters are precision devices; the cheaper meters tend to use discrete resistor networks, which are not as precise.
3) You will need a meter that can measure a millivolt and a milliamp. If you work primarily with amplifiers, almost any meter will provide this resolution. If you get a precise meter, then its resolution and accuracy will be satisfactory too.
4) Lastly, "features" like hFE and capacitance are bonuses that are common on cheap meters simply because they are cheap to implement. The branded ones offer features like temperature, RMS, temperature and so on.
Fluke has always been the industry standard around the world, but there's nothing wrong with Meco or even the mid-level UNI-T meters.
An analogue meter (even the ones with a FET at the input) exudes the warmth of nostalgia and is an excellent companion to a valve amplifier. If you can look beyond the nostalgia, however, analogue meters are not worth it. The biggest problem is with parallax error -- instead of a quick glance at the LCD, you have to move your head and sometimes your body to read the dial correctly. Apart from that, you have adjust zero-error when you switch ranges. I have a friend who owns a Tek DSO, a Fluke 87V, an HP 3478 and other relatively modern test equipment. He also has a pair of MY reading glasses borrowed during a hilarious evening trying to troubleshoot a faulty IF stage with an Avo 8.
Using an analogue meter nowadays is the equivalent of using a cut-throat razor to shave. I'm not sure it is worth the effort it takes to use them correctly.
Best of luck.
~hp