I am affiliated with neither of these products, I'm just sharing my opinions on each of these products to maybe help someone in the future who may be interested in buying either, or someone who is just interested in opinion.
I have owned GR3 since June 2011 and am getting ready to purchases Storm Predator 3.6 (Ive been using the trial for awhile now). Today I used Storm Predator all day to use all of its features in tracking the supercell thunderstorms in west central Texas today that then turned into a thunderstorm complex as it moved toward the Mexico-Texas border. The following that I created is a comparison of each radar based on different characteristics that make up a radar. Hope you enjoy and if you have any comments feel free to post!Display:
Storm Predator enables you to use your own preference for the display. The radar for SP can be in oval form, rectangular, full screen, or mini mode. In the radar itself there is also the option of adding a radar beam. This is used just for looks but it looks really awesome. GR3 is viewed in a rectangular format but it enables you to have full customization of the background of the radar, whether a color or a topographic background, while SP gives you a standard topo background. Overall I would say SP gives a better display than GR3.Color Tables:
SP enables you to choose the color display only for the base reflectivity radar and not for any others, while GR3 gives you full customization for all of its radar products. Obviously GR3 wins this battle.Radars:
SP uses the radars produced by the NOAA to display for personal use. These radars include base reflectivity, base velocity, echo tops, VILs, 1 hour storm precip., storm total precip., long range base reflectivity, storm relative velocity, and composite reflectivity. GR3 has over 20 radars including base reflectivity in 4 different degree positions (0.5,1.5,2.5 and 3.5), and 4 different base velocity positions (0.5,1.5,2.5, and 3.5). GR3 also has other storm relative velocity positions, and displays spectrum width and VWPs. So overall, GR3 wins with the variety of radars.Radar Smoothing:
GR3 does an excellent job with radar smoothing while in my opinion, SP's smoothing is one of its main weaknesses. I dont even use smoothing when using SP.Magnification/Zooming:
At first, I thought SP's magnification was horrendous, but I learned that it does have some zooming controls, though not as good GR3's. GR3 enables you to zoom in very close while keeping the radar very smooth, a feature that SP lacks (But its creator says they are fixing in one of its next updates)Looping:
This is a toss-up between the two based on your own preferences. I like SP better because they display up to 24 images in its radar images for using, which I can all save in a single file or seperately, while GR3 stores (I believe 20 images) and you have to store the images one by oneCustomizations:
If you are looking for a fully customizable radar, then GR3 is for you. If you are looking for a radar program that is pleasant to the eyes, easy to use, yet still shows nice information, then SP is for you. SP has a storm tracker built into it that I use quite a lot because it is pretty accurate and is based on user inputs. The program also enables you to view NOAA related sites withing the user interface without closing out the radar which I like ALOT. It dosent sound useful but it is to me. GR3 is completely customizable from start to finish, and you can add trackers and such to the radar from websites for free, just learn how to do it (Not that hard).Pricing:
GR3 is $80 only through download, while SP is $50 for a cd-rom or $40 through download. So obviously SP is much better.
Hope this helps some people in determining which to use. I am very fortunate to save my money enough to purchase both of them! I use SP more than GR3 for its user friendliness, but I still enjoy GR3 very much. They are both great products and I'm sure any weather junkie would enjoy both products. ENJOY!