Do looks actually matter? In this instance.. in some ways yes..
- Size - consider your storage availability, the size of your hands (& fingers) and whether the size affects the battery life/duration or amount of power (wattage) - the more battery life & power the better.
- Speaker volume - no point having a cheap speaker if you're unable to make out whats being said.. or even worse, so people can't make out what you're saying!
- Display- clarity & size - the bigger the better! Make sure it has a backlight option.
- Controls - intuitive controls.. are the controls big enough to operate even when you have gloves on? Does it have a 'lock' switch so you can't accidently make changes to the set up or accidently turned on?
- Battery - rechargeable? Lithium? Spare battery?
- Power / Wattage - most handhelds are a maximum of 5Watts but please check that the one you're looking to purchase is no less than this
- Durability
- Colour - though most handheld VHFs are black, you can buy white & yellow so its easier to spot in your kit bag or locker
- Floating & waterproof- helpful even if its attached to you.. though this can be solved by putting it in a waterproof & floating bag like Overboard's VHF case