The only problem with sitting in front of someone else's radio is that they will have tailored it in subtle and not so subtle ways to their liking. While I would definitely enjoy showing my K3 to anyone who wants to take a closer look, I will back up the configuration first so I can restore it later because the only way the other op can make a true decision is to play with things like RX equalization and the sort. For me, at least, after six weeks I'm pretty much leaving the configuration in my K3 alone. The first couple of weeks I was changing things every day. No way do I wish to loan my radio for six weeks nor have another ham move in for that period of time! :laugh:
I'd suggest reading the eham.net reviews, but also advise to read some of them with a huge grain of salt as I'm convinced there are hams who could break an anvil with a rubber mallet. ARRL and other magazine reviews are also good resources. Even after all that, you really have to live with a radio day in and day out for years before you truly know its personality. And trust me, they have personalities.
What is tricky is to determine your intended use. Are you a phone operator? Look for features that make phone operation stand out. How about digi modes or CW? Likewise, look for features that stand out for your interests. That is tricky when first starting out as it may not be immediately obvious how those features will be an asset. Also, don't just focus on how pretty the diplay/front panel are or price. Considerations should also include receiver performance and transmitter performance. Often overlooked are transmitted phase noise and other artifacts which impact our neighbors on the bands. While the specs may meet Part 97, the cleaner our signal is, the better we meet the spirit of the regulations as it should be our goal to exceed the minimum standards.
At any rate, don't get into a rush and do your homework. Above all, enjoy the experience.
P.S. Personally, I'd rather spend a pile of money on several radios than on one.