Please note, the Uniball has released the Uniball 307 pen . This is a newer version of the 207, with some subtle differences. It's not clear that the 307 is a direct replacement to the 207, but it is a newer model in the same series.
Also known as the Uniball Signo Gel 207 retractable and the Uniball 207 RT, this is a very popular pen. It's widely available and is competitive with almost all the pens in its class. The Uniball 207 is sold in almost all office supplies stores, has multiple varieties and has affordable refills that are readily available.
There is significant confusion around the Uniball 207 line because of the multiple varieties that are sold. The 207 is the standard model but it comes in models with a chromed plastic tip and others with a white plastic tip. The pens are otherwise the same and all have a metal pocket clip.
The Uniball 207 is a retractable pen that is best known for popular advertising campain in which Uniball promoted its ink, which is apparently not susceptible to check washing. The pen is widely available in red, blue, and black but at least 5 other colors (like pink and green) are available. Sizes range from 0.38mm to 1.0mm, with 0.5mm and 0.7mm being the most popular sizes.
The 207 is a popular office pen and can be branded for promotional handouts, though it's not as popular for either application as the Pilot G2 .
The 207 is available in a wide range of purchase options, from a multi-color 8-pack , to office-friendly single color 12-packs , to four-packs , and single pen sales. 207 Refills are normally sold in two-packs, where you'll typically pay about $2 per refill (so expect to see them sell for $4-5).
The 207 is a popular day-to-day pen, but if you really like it you can check out the 207 Premier, the 207 LTD , or the 207 BLX . The 207 Premier is the affordable luxury version also known as the "executive pen," while the LTD offers color variants, and the BLX offers different varieties of black-like shades, for example a green-tinted black ink.
The Uniball 207 is one of the best retractable affordable gel pens available today. It's not as highly regarded as some others because it's so commonplace but it really is quite good. The ink dries fast and the pen is probably the most comfortable in its price range, more so than the Pilot G2 or any of the other 207 varieties. The standard 207 retractable is, unquestionably, the best of Uniball's 207 varieties, even better than the more expensive 207 Premier, the 207 Gel RT, or the 207 Impact RT.
The 0.7mm model is the most popular in America, but the 1.0 is exceptionally smooth. It can be hard to find, and it tends to put out too much ink for lefthanded writers, but it's still a lot of fun to use if you are working with single-sided sheets or thicker paper. The 1.0mm (Bold) refills are relatively easy to find though, and they can be swapped into other pens without any problems.
The 0.5mm and 0.7mm are OK, but they do not have excellent smoothness. If you want these sizes you might want to explore other options -- they aren't bad, but they aren't the best either.
For the money, the Uniball 207 RT is very tough to beat. Don't get fancy with it though, get the standard model and you'll be happy with your purchase.