The difference is plain! One is sold in petstores and the other in a hardware store! Now let me tell you a secret! There are 3 or 4 manufactors of fluorescent lighting tubes. Other companies order a certain tube (or kelvin), put their logo on it and sell it! Therefore, the tubes themselves do not differ.
The Kelvin does because of different phospors used in the tube. However, the most important factor is deciding on the application. In this case its a freshwater planted tank. Taking into consideration the kelvin at noon which is 5500K, getting tubes around that range is optimal for plants. Im not saying you cant get different tubes of different k values! Most people, myself included mix in some 6500K to acheive a better looking tank however one has to remember that the plants do not benifit immensely from higher or lower k values. What will really make plants grow is lighting intensity!