I was never impressed with these digital photo frame products. While it sounds great initial, especially for a gadget fan like me, I always think that it is the wrong way to enjoy personal photographs. Isn't the screen too small? Isn't it too painful to setup? Aren't they too expensive? Well, after some research, I bought a few Philips 6.5 inch digital photo frame as Christmas presents for family members. The reasons for choosing this particular frame are:

It has very high resolution for the frame size. Many other brands have larger screen perhaps, but not as high resolutions.
It does not have wifi, dialup, subscription, etc. While those things sound great on paper and for techie, I cannot see a grandparent using those. Memory cards are very cheap these days, you can buy a 1G SD card for $15 when discounted. Just Fill up a card every few months and mail or give the card to the frame owner.
Clean look -- this is a personal taste thing.

I wanted to load up some pictures for them before I give them the frame at Christmas, so I opened one today and played with it. I was, impressed.

This particular frame is very well designed. Now I understand why it always had good reviews. Some good points are:

The LCD is very good, high resolution, good for the screen size. The viewing resolution is 720 x 480, and the viewing size of the LCD is 6.5 inch, not 7 inch. (Some vendor list it as a 7 inch frame, some as 6.5 inch frame).
The stand, the part that connects to the frame to make it sit/stand, is very heavy -- because when the frame is on display, the stand makes it almost vertical, and the heavy stand/leg makes sure it does not topple over, good design
It has some nice time management feature -- You can have a on/off time daily, you can change the display brightness during "night time". Both Feature lets you make the frame more "bedroom" or "bedtime" friendly.
The user interface works !! It has several button on the top of the frame at the back. It is designed so that when you hold the frame, you can press the buttons with your forefingers with both hands. There are on-screen soft labels to tell you what the buttons do while you are using the user interface.
The frame is designed to be used plugged-in, but it has an internal battery. So you can disconnect it from the AC temporary if you want to pick up the frame to look at the pictures, or to pass it around. A well thought out feature.
The best way I find to load the frame with picture is just to use a memory card. For example, one can load up a memory card with family photos and send the card via (postal) mail to a grandparent or something.

Now some bad points, or tips:

If you want to use a large SD card to store lots of pictures (which I recommend), you have to make sure you format the card in FAT32 format. Otherwise there is a limit on how many pictures (files) you can put at the root directory,...
The photo frame software will not look inside folders on your SD card for pictures. You have to put everything at the root directory. Hence the (1) issue above.
The sequential slideshow order display pictures in the physical order of files placed on the SD card. This makes no sense to me. I wish it would sort by date or at least file name.