Here are the advantages and disadvantages of reading programs. From DyslexiaMyLife.org
However, in my opinion, you are asking the wrong questions. The most important question is, would Barton be a good fit for your child?
There are only three reading methodologies that have a really good track record with dyslexics. Of these three reading methodologies, there is one outstanding program for each. These would be Lindamood-Bell LiPS, ABeCeDarian, and Barton. These are all programs that are worth using and that get results. However, which of these works best for a child and family depends on the specific characteristics of the child and the family circumstances.
In other words, it would be better for you to start with your child. What is your child like? Do you have any testing results you could post? Parents should always start with the child, then choose the reading methodology -- not the other way around.
How they differ from one another, and which type of student is likely to respond best to which methodology. If you can post more specific information about your child, that would be very helpful too.
For a parent, the first thing to look at is the development of phonemic awareness skills. The Barton website has a screening program you can use to determine if your child is ready for Barton. Alternatively (and the approach I prefer), you can get the book "Reading Reflex" by McGuinness. Read the first 3 chapters, then give your child the assessments in the book.
Barton works well for children who can pass the Barton screening, who do not have working memory problems, and who do well learning by means of rules. Disadvantages are that it is very slow to get to vowel-e words ("cake", "bike") that are common in a lower-level text (does not teach this until level 5). This can make the program seem very laborious to parents and children. Children with working memory issues tend to get bogged down after level 5 because of the working memory "overhead" required for learning and applying rules.
LMB LiPS teaches phonemic awareness skills in the most thorough way of all the methodologies. This is why it is recommended for a child who does not pass the Barton screening. However, not all children need the work in LiPS to acquire phonemic awareness skills. For those who do, though, it is invaluable. The portion of the program that extends beyond phonemic awareness skills works well for children who learn well by means of visual inputs. LiPS is the methodology of choice for children with apraxia of speech.
ABeCeDarian and Barton both teach phonemic awareness skills at the front-end; they simply do not do it as in-depth as LiPS. The ABeCedarian methodology is concept-based rather than rules-based and tends to work really well for about 4 students out of 5 who have difficulty learning to read. This methodology works well for "big picture learners" who benefit from understanding a concept first, then learning how to apply it.
If money is a big issue (and even when it is not), I recommend starting with the "Reading Reflex" book. Check your library; otherwise, it is widely available in bookstores and online for about $25. After doing the assessments, you can use the exercises in the book to see how your child responds to a concept-based methodology. After about 30 hours of working one-on-one with the book, both you and your child will know whether or not it is working. If it is working, I recommend switching to ABeCeDarian, which uses the same methodology but which provides better materials to work with and also online support by means of the Yahoo group by the same name. If your child does not respond well to the exercises in "Reading Reflex", then he/she may need LiPS (which offers both phonemic awareness and decoding instruction) or LiPS (for phonemic awareness) followed by Barton (for decoding).