Make an Investment if you like sewing or see yourself sewing regularly. When I was first out of college, I decided to purchase a cheap machine because I knew I liked to sew, but didn’t know how often I would use it. I almost gave up sewing because of the frustration from that machine! So, I suggest making at least a small investment (around $350+ MSRP, but you can always find sales and good refurbished machines for cheaper). Also, if you enjoy sewing, you will likely outgrow the most basic machine quickly and will be looking at making another purchase in the near future.
Auto Tension is a must! This was the worst thing about my cheap machine. Every time I switched fabrics, if their thickness was even slightly different, I would have to sew a scrap piece of fabric to test and adjust the tensions every time - maddening! If you do this when you sew - there is hope out there. It is absolutely worth the money to get this - it will wind up saving you hours!! Not all brands/models have this feature, you’ll have to watch for it.
Automatic Buttonhole stitches are obviously handy for clothing, but I have found myself using buttonholes a lot for home décor (curtains, pillows, etc), baby car seat covers, even as jewelry fasteners. Look for buttonhole features that allow for variable hole length that can be based either on your button size or a specific length.
Walking Foot is used when machine quilting straight stitches. It has dog feeds (the little teeth you can see under the foot) on the foot itself to help move all the layers of fabric together when you quilt. Make sure the machine comes with or has a walking foot available for purchase.
Needle Down feature tells the machine to stop the needle in the down position whenever you stop stitching. I absolutely love this feature and won’t buy another machine without it. It is invaluable when I do appliqué, make stuffed animals, free motion quilting, even piecing sometimes. Not all brands come with this and in some brands this only comes with the higher end machines.
Free Motion Foot and Dropping the Dog Feeds are used in free motion quilting (not straight stitches, example below), the machine has to be able to “drop the dog feeds” (which prevents the fabric from being pulled to the back of the machine) and come with a free motion foot or have one available for purchase.
Decorative stitches typically come with the higher end machines. The image above shows examples of a few decorative stitches. These are a nicety – they make fun embellishments on clothes and burp rags.
Knee Levers come on some of the higher end machines and allow you to use your knee to lift the pressure foot, leaving your hands free to guide or hold fabric. This feature is extremely helpful when doing a lot of turns in applique or any time you need both hands on a project.
Embroidery only comes combined with sewing in the very high end machines. You can expect to pay in the $2500+ price range for a combined sewing and embroidery machine. I suggest buying a separate embroidery machine from your sewing machine. You can get the 2 machines for less than the price of the combined machine. A combined machine has more points of failure and when it needs servicing, you are out 2 machines until you get it back. Also, I have found that there have been many times when I am sewing while the embroidery machine is doing it's thing - multitasking at its finest! :)
Servicing your machine is important. Find out if you have a store locally that can service your machine - be sure to mention the brand because some machines require special training to maintain. It's better to know up front if you will have to pay for shipping your machine to get serviced.
Ok, I tried to hold off, but I just have to plug my Janomes. I have 3 - sewing machine, embroidery machine, and serger - and absolutely love them all!
I hope this is helpful information. Please ask any questions about features you've seen or don't know what they are used for, I'd be happy to answer them or get in touch with someone with answers and pass the knowledge along. :)