Had I not owned an older Harmony 700 remote, I might have given the newer 650 three or even four stars. But while the 650's lighter gray color makes reading text below the keys (like alphabet letters under the number keys) easier than the 700's, there are way too many downsides to the 650 to give it anything but a overly gracious two stars.
The 650 is uncomfortably lighter then the 700 (no, it's not the regular versus rechargeable batteries as the Best Buy salesman tried to tell me) and the balance is worse, making it borderline cumbersone to hold and operate. It's glossy finish is almost cartoonish. The display is admittedly slightly brighter than the 700's, but the 650's viewing angle is poorer and quite annoying by comparison. And the 650's key backlighting is far less attractive, being dimmer and an unsightly yellowish color (the 700's is a nicer white).
But most annoying (besides upgrading from the older software, which I'll comment on later) is the horrendous lag on the arrow keys that makes channel surfing through things like on-screen program guides at best frustrating. (As an aside, the 700 was much more responsive -- I've put it side by side with the 650, so it's definitely a difference between the remotes). At first, I thought that maybe the 650's lag was a faulty remote, but replacing it with another 650 made no difference.
After over 5 years of flawless service, my 700's keys were showing wear (the backlighting was coming through around the edges of several of the more often used keys), and for some reason, Logitech chose to discontinue it. The 650 was arguably better (at least on paper), supporting more devices (I was already at my limit with the 700 and was thinking of adding another one or two). I was comfortable trading off additional devices for not being able to use rechargeable batteries (another advantage of the 700). So I was unpleasantly surprised when my new 650 was recognized by the MyHarmony 7.7.0 software I used with the 700, but a message in red text said I was still at my limit for devices and couldn't add any more (meaning I was not able to approach the 8 supposedly supported by the 650).
I called Logitech and got a support person whose broken English was not only nearly unintelligible, but clearly she couldn't understand me either. Still, though it was quite an effort to communicate with her, she seemed very knowledgeable about the product and said the limitation was with the older software and that I needed to upgrade to the newer version to benefit from all of the 650's features.
I had spent hours creating very detailed activity pages and custom hard key programming for all of my AV system components, and I was not willing to redo all of this if that was a consequence of upgrading the software. But she assured me everything would copy over unchanged and I would be good to go. Unfortunately, upgrading to the new software meant I could not keep the older software on my computer (apparently they are completely incompatible), and like a fool, I believed her and went ahead with the upgrade.
I'm sorry to say that my experiences with most support people have not been all that good, and she did nothing to change my pessimistic opinion. My programming did NOT copy properly. Some of the older functions were no longer supported by the "upgraded" software (like leaving a blank key on an activity page to make grouping of commands on various pages more sensible and intuitive), and only a few of my commands in each of my activities were actually properly replicated, interspersed with a random and incomplete sampling of stock Logitech commands for my devices (which was limited in most cases, very limited for devices like my Roku box, and non-existent for my Chromecast device, the latter requiring jumping through hoops to properly set up).
Well, I was in deep already, so I went ahead and tried to reprogram my new remote to emulate my old one as best as I could. Fortunately, I still had my 700 as a reference, and also to use for custom key programming on the 650 to replace several keys that were no longer in Logitech's stock keys for various devices (like no DVR command for my DISH Hopper -- a huge oversight on Logitech's part).
[Some of these problems I immediately discovered on the phone as Logitech's support person walked me through the upgrade process. When I told her that things didn't copy properly and blank keys on screen programming had disappeared, her response was simply that she knew that -- doubtful since she said earlier that everything would perfectly copy over -- and I would enjoy the new software much better anyway (a truly patronizing response since one spends very little time time programming the remote in comparison to the amount of time they actually use it).]
Eventually I was able to recreate something that approximated my original 700's setup, but the lag on the direction keys is so frustrating that I find myself still using my highly worn 700 and a second remote to overcome the 700's number of devices limitation. I would NOT recommend the 650 to anyone, but instead suggest that if they want the 650's functions, they search for one of the few remaining new 700s on the web and get it instead. It may be a bit more expensive, but it is by far a much better remote. (Logitech still supports both versions of their remote programming software, and the new software will work with the 700 as well. So if someone likes the new software better and aren't concerned about some of the differences with the older software, they can choose it instead.)