TALK TO PEOPLE! Ask ladies at quilting groups, churches, neighborhoods, etc. what type of machine they have and what they like/ dislike about them. You quickly find out which ones to avoid! Also, ask yourself how much you will be using it. If you're just mending, get a cheaper machine than if you are wanting to become an embroidery queen.
Most stores like Joann/Viking have many models for test-driving. Also, any NEW machine should come with classes for use and a maintenance contract. Don't be talked into a machine that is more expensive than your means or pay on time - you end up paying more than the machine is worth.
Also, visit some sewing/ vacuum stores in your area and talk with WOMEN who SEW! Men are nice enough, but unless they sew REGULARLY, they are often useless when asking for comparisons. Do not be bamboozled by 'my wife prefers this one' or 'my mom has this one', it probably isn't true and there is probably a push to sell that particular model that month.
If you can, ask your friends if you can try their machines to see what you like and don't like about them. The more time you can invest in your research, the happier you will be when you decide to purchase something. Remember, that you are the only one who knows what will fit your budget and creativity.