C.,
I had some samples of Next Step (two whole containers) and some coupons for huge discounts on it as well ($11 off!). So I bought it and used it with my DD because it made financial sense. Since it is made by the same formula company, I figured it would be the same if not better at her older age to use it. If you have the same incentives, then I would say go ahead and use it... otherwise, it's probably not necessary.
For my son (now 6 months), I have received samples again of Next Step and more incentive coupons... I think I have 3 cans of the Next Step already. Once again, I plan on using it for reasons of economy.
As another Mom pointed out (and this was substantiated by my lactation consultant/nurse), as long as your child hasn't shown any difficulties or allergies, you don't have to wait until the 1st birthday to start the switch to whole milk... you can start at around 11 months. I may have mixed it 1/2 for a few days, then just went to one bottle, slowly replacing it with another and another until DD was totally on whole milk. (My LC/nurse said there is no "whole milk fairy" that waves a wand and says, "Okay, it's time!" on the first birthday. As long as you haven't had other complications or have other hesitations a month/6 weeks before 12 months is fine.)
I know that formula can be expensive... and I only formula fed my daughter between 8 and 11 months! Whatever way to save money is great... of course, as long as it is fine for the health of the child and in my case it was.
I also made the switch between bottles and sippy cups during the switch to milk. I started by putting juice in sippy cups, my DD NEVER had juice in a bottle! As we moved to 1/2 formula and 1/2 milk and then just milk... it was all in a sippy cup. That way as the taste changed, so did the cup she drank it out of. We never had a problem transitioning... used NUBY.
Enjoy your son!