Re: Consider further search optimization, hesitate between MySQL LIKE and ▒FULL-TEXT▓
If I had to choose between the two, I would choose a full text search. It is much faster and more provides more relevant results, and would be a modest improvement over the current search function.
However, the cons to this search may be deal breakers. None of four character, stopwords, and other 'cons' can be changed unless you are on a dedicated server. Maybe the largest issue with the full text search, which I don't think has been mentioned, is numbers and special characters do not work very well, and often return very odd results. While a full text search works well with basic queries containing words four alpha characters and greater, no other searches will benefit from this technology, no matter what changes are made to the settings on your server.
For truly relevant results, X-Cart needs a custom engine that takes into account word density, position, section, stemming, and incorrect spelling. This is what I had to do with the Smart Search, it was the only option that worked.