So you want a portable generator (genset) for power outages or to utilize some creature comforts while you are roughing it.  Most likely a gasoline powered generator will meet your needs although diesel, propane, and natural gas powered generators (and conversion kits) are available. 

Thoughts to ponder before you buy:

1.  Determine what electrical equipment you will NEED to operate vs what you would LIKE to operate.

2.  Most portable generators list their output in WATTS.  Watts = volts X amps.  A 100 watt light bulb will of course consume 100 watts.  Most electrical devices list there voltage and amps consumption.

3.  If the device(s) you wish to operate have a motor (refrigerator, washer, etc.) bear in mind that the initial start-up wattage may be 33% or higher than its running wattage.  That refridgerator may run at 1500 watts but at start-up (compressor kicks on) it may pull over 2000 watts for a few seconds. Also consider what other plugged-in equipment might start at the same time.  A 4000 watt rated generator pulling 4500 watts even briefly should trip the circuit breaker cutting power to everything.

4.  Size matters!  That 15,000 watt generator may be able to operate most of your household gadgets but at 500 lbs it may not be considered portable by some!  The cute little 700 watt generator may be light but maybe you may wish to operate more than your TV and radio. 

5.  An advertised 4000 watt generator most likely will refer to its short term SURGE output.  At a continuous output of 4000 watts it will overheat rapidly (most engines are air cooled).  This same generator will most likely be rated at less than 3000 watts for continuous operation.  Generators made for the US market operate at 1800 or 3600 rpm.  The 1800 rpm units seem to last longer and are quieter while the 3600 rpm unit seem to be smaller and lighter for the same output.

6.  Decibels...NOISE.  Most gensets operate from the high 50's to the low 70's decibel level (measurement taken at a distance of 7 meters from the source).  An increase of 10 decibels means a DOUBLING of the noise.  The size of the engine and the muffler matters here especially if you will be using you genset for camping (NEVER INDOORS!).

My personal choice;  I have a Contractor Line 4000 watt gasoline powered generator (4 stroke engine, NO mixing gasoline and oil) weighting a little over 100 lbs.  Could I justify an 8000 watt generator? Yep but not the added price and weight.  My generator is for power outages of short duration.
The Homier unit, Powerwise, Chicago Electric, Cummings, WildFire, and DuroPower generators are all built in China.  These are good units for the money spent, they are a lower cost alternative for someone who perhaps wants a generator for occasional use when power is not available. The engines are a Honda clone (6.5 hp or 196cc) and their massive muffler meets the NPS noise standard of 67dB at 7 meters.

Remember to read your owners manual and follow ALL your local codes before using!  ASK an expert!  Don't guess or assume!  Dozens of people die in the US due to the improper use of their gensets!