Is it worth really buying a Fluke for hobbyist use?

I think you should make sure you select a multimeter that answers the questions you need answered. Or start with a cheap one, and if you need more features / better accuracy, get a better one.

Most folks working on digital electronics need to know if:

• Is this signal high or low?
• Is this signal switching?
• Is this wire continuous?
• Is my transistor PNP or NPN, and is the Radioshack package correct? (it wasn't, once, for me)
• How much current is running through this section of the circuit?
• What is the duty cycle of the PWM signal? (This is easily found by doing a little bit of math based on the voltage)

Really, to solve all those problems, a $5USD digital multimeter does all that and more.

If you need to measure capacitors, inductors, are panicky about your duty cycle, or need tight accuracy, or you need the thing to survive falling down a waterfall or being inside crazy EMF fields or your'e gonna beat the thing up, I'd look for a Fluke or something.

If you need to watch really fast signals, you should be doing that with a logic analyzer or an oscilloscope anyway.

A brand-name multimeter is absolutely worth it.

Fluke multimeters are some of the most reliable out there. They respond faster than most cheap DMMs, and most of them have a analog bar-graph that tries to bridge the graph between analog and digital meters, and is better than a pure digital readout.

Also, one thing that I do not see mentioned, and is very convenient about them is that they run forever on a single 9v battery.

It may seem a trivial thing, but I've used a lot of no-name DMMs, and they all go through batteries every few weeks, particularly if you forget to turn them off.
Flukes, on the other hand, turn themselves off automatically, and I think I have had the same battery in mine for 3+ years.

It's extremely nice to know that your battery powered equipment will just work when you turn it on, rather than having to try and track down the proper batteries so you can take a measurement.

The big thing is whether or not you're ever likely to be using mains voltages - quality gear like Fluke has significant safety features to prevent injury when things go bad. For hobbyist use, issues like accuracy, robustness and lost time when it breaks are much less important than for professional use, so the benefits of an expensive unit are much lower. If the decision is between cheap DMM plus a cheap scope, or an expensive DMM, the former would usually be more useful to you. Also consider a used name-brand over a new cheapie. You will usually get a better bit of kit for your money, albeit maybe a bit bigger and less shiny.