HI GeekDad, welcome to the forum.
There was a post yesterday on another subject where the writer also commented on Qimage & GF
http://ddisoftware.com/tech/profile-prism/is-this-a-calibration-issue/30/
That says it all really, free upgrades with Q, easier to use, very flexible for printing any size with multiple images on the paper in any position and excellent quality.
Qimage does have what are regarded as the "best" algorithms for re-sizing images and because it  sends an image to the printer at the printer's native resolution, whatever the print size, excellent quality prints are the result as I'm sure you know. You don't have to think about "what resolution shall I use", Q does that for you once you decided on the linear size of the image.
No apologies for that 
Terry.

Fred-
First, a disclaimer.  I quit using GF years ago.  That's because images are larger to begin with these days.  However, it has its place.

Do not confuse interpolating an image up for printing with enlarging a cropped area before editing and refining it in an editor.
Nobody, except Mike (and somebody that may have reverse-engineered it), knows if he is using multiple interpolations.  It was shown years ago that multiple interpolation in small steps is (generally) sharper than a single move when making extreme increases--under certain algorithms.

  I appreciate all of the comments thus far on the subject. As I said, use Qimage for almost all of my printing- I believe it it less expensive than GF as well, plus Mike has responded to any of my tech support questions very quickly. Plus the update process is great. I had downloaded GF and tried it on a picture that I had taken with a Sony Mavica years ago- where it stored images on a 1.44MB floppy (those were the days), and printed it out on 5x7 paper. I printed the same image out using Qimage (hybrid interpolation and sharpen=11). I thought that the Qimage  picture looked slightly better, ignoring the GF watermarks in the demo version. Hopefully I will be able to contribute every now and then and don't always ask questions.

They're two different animals with two different purposes.  Yes, Sharpen 11 is extreme but he is obviously doing an extreme blow-up (considering the original) and the Smart Sharpen/Interpolation are a final print issue w/o artifacting.

GD,
I still think that Qimage is the way to go if you ask here HOW to: and get the hang of Qimage.
First of all, I placed an 8 meg image into Qimage and set the size to 16 x 20. Qimage reads out at 147 PPI.
From long experience, I can promise you that 147 PPI would be far more than Qimage need to produce a perfect 16 x 20. (It's all in the interpolation)
But you apparently do not have a printer that will make a 16 x 20 for your friend and Costco will make it.
Qimage has a feature called Print to file. To find it, click FILE and PRINT TO. and select FILE.
Set the PPI to whatever Costco says is optimal, set the size to 16 x 20, and you can set the color space to either RGB or ADOBE or whatever Costco says is best. If they will supply a copy of their printer profile for you, you have the ability to create the print file with their printer's profile.

Regardless, Qimage's interpolation will make a print file for you that is superior, and you need not purchase other help.

Try it! You will be amazed!
Fred

I am attaching three snaps to give you the idea.
One of the boxes that appears after you click PRINT is snap 21. There you select the file type you wish to create.
The next box that appears is "the where do you want to place the image.
My choice by default is to let it appear in the same folder that I am working from.
Click OK and Qimage will process that image and produce a print to file image which will appear in the same directory having a QP prefix.
See last snap.

Fred

I'm running Studio 2008.213 and just reinstalled on a new configuration. I didn't remember the Lifetime Updates part, and since I'm still breathing I thought to drop by. But my interest is in print-to-file. What I'd like to do is up-rez an image for article on software comparing the output of various programs. Doc McHugh wrote a similar piece on resizing for his site but didn't compare Qimage output to the other programs and I'd like to do that for the piece.

So the question is: Any advantage to upgrading for this purpose?

Maybe I should add that I'm happy as is and have been printing my old stuff (3.3MP) on 11x17 Ilford Pearl, and 6 & 8 MP on 13x19 and it's all looking good.