The bike is... "decent." I honestly would not buy it. DiamondBack is not a respected name in road cycling, and most of the components on that bike are either known to be of poor quality, or are no-name (which usually implies poor quality). The Sora group basically sucks. Also, the weight is not listed, but I doubt it's very light. Also, this bike is a "compact double," meaning it has only two chainrings ("gears") in front, and thus provides fewer choices of gears than other bicycles with three chainrings. Particularly, it has fewer low gears. If you plan on doing a lot of hill-climbing, you might find this frustrating. Also, compact doubles require more careful alignment of their derailers, which might mean that you'll be spending more time fiddling with it to make it shift well. This is particularly true for cheaper component groups like Sora, which tend to need frequent adjustments.
If I were you, I would look into some of the major road bike manufacturers, like Giant, Trek, Specialized, etc. Each manufacturer is going to have one or two bikes under $700, and they'll all be a much better purchase in the long run. If this is your first road bike, I also advise that you buy it from a local bike shop in your area -- fit is incredibly incredibly incredibly important for road cycling. I cannot stress this enough: you need to buy a bike which fits you, or you're just wasting your money. If you decide to do rides in excess of 10-20 miles, a poorly-fit bike can seriously injure you, or at least make for a miserable experience. I mean it. The truth is that not every bike will fit you, even expensive ones. You need to try a number of them out and find which ones are best for your body. Literally, try 6-10 different road bikes before deciding to purchase one. Do not buy a road bike without getting some kind of fitting from your shop. If you purchase at a local bike shop, you will get free servicing and fit adjustments. If you're new to the mechanics of bicycles, this is entirely worth it. If you don't want to pay a big mark-up at your local bike shop, look for sales, ask for a discount, or get involved in a cycling club in your area. Many shops offer steep discounts to local cycling club members.
Now... for accessories and clothing. You probably won't need any fenders ("mud guards") on a road bike, because road bikes are really not meant for riding in the rain. The tires are very skinny, there is no tread, the contact patch is very small, and they can be very dangerous on wet pavement. They also tend to accumulate a lot more particulate debris when they're wet, which means far more flat tires. If you insist on riding your road bike in the rain, you should look into tires meant for the purpose.
Lighting, on the other hand, is a very normal accessory for a road bike. You can buy cheap lights that simply clip onto your handlebars, and they're good for perhaps 10 mph or so. If you intend on going faster at night, you'll need a substantially better light. I tend to keep 20 mph or so on flat ground, often hit 40 mph on descents, and have gone through numerous lights. The only light that has pleased me so far is a $400 HID model that's about as bright as a car headlamp. Do not try a fast descent with a clip-on AA-powered headlight. Trust me, don't even try it.
"Clipless pedals," which lock with cleats on the bottom of special shoes, are not quite required, but are such a luxury that almost everyone eventually gets them. If you're doing serious hill-climbing, one slip of your foot on normal platform pedals can result in serious injury. Also, clipless pedals give you a 10-20% boost in your effective power delivery, and allow you to use all of your leg muscles, rather than just your quads. Over time, this will lead to less likelihood of injuries like knee pain, which often are caused by an imbalance in various muscle groups. Because clipless pedals immobilize your foot, they do require some care in adjustments. Be careful not to ride very hard on them until you're absolutely sure they're in the right place for your pedal stroke.
Clothing varies tremendously by season. Here's a list of all of the clothing that I wear in various ranges of temperatures:
70+ degrees F: cycling shorts, full-zip short-sleeve jersey, ankle socks, half-finger gloves, helmet.
60-70 degrees F: cycling shorts, short-sleeve jersey, arm warmers, leg warmers in my seat bag, ankle socks, half-finger gloves, helmet.
50-60 degrees F: cycling shorts with tights over them, or cycling shorts with leg warmers, short-sleeve jersey with arm warmers, wind jacket, wool socks, shoe toe covers, full-finger gloves, helmet.
30-50 degrees F: cycling shorts with tights, long-sleeve jersey with optional microfleece layer, wind jacket, wool socks, shoe toe covers, microfleece skull cap, full-finger gloves with liners, helmet, helmet cover.
I rarely have any opportunity to ride in temperatures below 30F, so I can't speak on that. I'd certainly just continue to layer, however.
Hope this helps, and happy riding!
- Warren
It has the standard 50t/34t compact double setup, meaning it has almost the same range of gears as a 52t/39t/30t triple, but doesn't go quite as high or quite as low.
