Looks like the LC Star is for small children:
From their website:
The PARI LC® Star was designed for treating the deepest part of the lungs or for those patients with smaller airways due to age or advanced disease state. The LC® Star is designed to deliver the smallest particle size of all PARI LC® Reusable Nebulizers with the highest percentage of particles in the respirable range.
So, I'd say you are probably just fine going with the star.
About keeping them sterile:
I don't think anybody can get or keep them "sterile" so I'm assuming you meant sanitized and or clean.
I have links on my blog and there have been numerous posts on the CFF's recommendations for sanitizing neb cups - you can boil, use alcohol or hydrogen peroxide once a week for sanitizing.
I prefer to use the germ guardian sanitizer <a target=_blank class=ftalternatingbarlinklarge href="http://www.amazon.com/Germ-Guardian-NS-2000-Nursery-Sanitizer/dp/B000G27DHA/ref=prime_sr_1_2?ie=UTF8&qid=1219583931&sr=8-2">http://www.amazon.com/Germ-Gua...&qid=1219583931&sr=8-2</a> , however that has not yet been approved or recommended by the CFF.
Through the course of a regular week, washing and air drying is what I used to do, then place them in an open type basket with a paper towel around and on top - others have said they put them in a zip lock bag. Once a week we would boil them in addition to the washing.
I never liked the idea of air drying on my counter for half the day - I love using the guardian, whether or not it is approved as a sanitizer, it for sure meets the guidelines for air drying and it is a heck of a lot faster. I wash them in hot soapy water, rinse and shake off as much extra water as possible, then put into the guardian. I feel better knowing they are clean and dry within 30 minutes and I can put them away - sitting around waiting for them to dry seem like it would contribute more to the chances of them getting something on them.