I purchased several Wal-Mart wired units in 2010 and they fulfilled my needs for the first 6 months of learning to ride again (I wanted average & highest speed, time, and the distance I covered). I tried a wireless unit, but it did not work as well as the wired units.
I then started to draw my ride routes on a website, to keep track of my weekly, monthly, annual rides and distance. I purchased a Garmin Edge 200, it was great for quickly uploading my maps, for that purpose it improved my information feedback. I was able to upload the route info in a "Fit" file to mapmyride.com and later Strava.com. Before the Edge 200 purchase I was hand drawing the maps, and posting the information I was getting from the Wal-Mart units. (I can not use the Garmin Connection because they do not have a web browser application, and I can not use Apple or Microsoft Software in my Google Chromebook).
I used the Edge 200 until January 2014, it is compact, small and moves from bicycle to bicycle without setting the tire size since it maps via GPS. For a holiday gift I received a Edge 705, an older Garmin Edge model with more function than the set menu of the Edge 200. I also received a Speed/Cadence Sensor (GSC -10).
I also joined Strava.com last year, as it gives me the ability to compare my rides, and sections of the rides with my history & other riders easily. I still like the sharing of maps with Mapmyrides.com, and the monthly calendar function of that website. But being able to follow other riders, and compare my rides with my history & others is also a very good tool that Strava has allowed.
The Mapping ability of the Garmin certainly expanded my riding feedback and assisted in making me a stronger rider. In the Bicycle group I ride with, many members use Strava and they use their smart phone with the Strava application, where i use the Garmin edge 705 unit instead. But now I have a cadence sensor that will communicate with the Garmin to help me make another improvement in my riding skills this year (Garmin Edge 200 can not add sensors).
There is no best Cycling Computer in my opinion!
The one you want is the one that fits your current riding needs. Less functions is best, when you are first learning to ride, or taking up the sport you enjoyed in your youth. Average Speed, time and distance may be all you need, and the cheapest units on ebay will perform that function reliably if you are in a dry area year round. You need to step up in price to get a reliable unit in high humidly, or rain country.
If you want to keep track of your riding performance a three ring binder with paper and using the info from a $6 wired unit could be perfect for your needs. I like the mapping ability that the compact Garmin Edge 200 provided, and now I have cadence feedback with the Garmin Edge 705 and having this info as an overlay on the elevation display. I feel that it is the right time for this cadence info feedback and it should improve my riding skills this year. .
But the mapping and cadence feedback would have been useless to me when I first started riding. I looked at several different cycling computers @ the September 2012 interbike show in Vegas, and at that time the Garmin Edge 200 I was using fulfilled all of my needs. One of the people I ride with several times a week, uses the Strava application on his Smart Phone and he has not purchased a separate cycling computer.
Maybe you do not need a separate cycling computer, but a smart phone application that will post your mapping and elevation information to a website. This might be a less expensive method for you to keep track of your information, if you are already using a smartphone and unlimited cell service..
I purchased a scratched Garmin Edge 200 used from ebay for $100 2.5 years ago, but I believe the Mapmyride & Strava applications are free to download and install on a Smart Phone. There may be other smart phone cycling application I do not know about that will also fit your current needs, I suggest checking with other riders in your area or riding group.