Well that depends on your needs. If you want to tour the spanish-speaking countries, then the basic set is enough. But if you wish to fully learn the language and everything related to it, then the investment for the whole set is worth it.
I found the method interesting for one level and then monotonous and boring for the other. It is essentially ONLY teaches you through matching pictures. No videos what so ever! No movies or films to keep you captivated. After the 3rd level, I switched off!
My kids have finished the 3rd lesson and they are trying their spanish on their English as 2nd language friends. Their friends say that they should learn better grammer. Does this mean that 1-4 is enough to be understood or that Rosetta grammer is insufficient? You decide.
The Rosetta Stone program is a lot of hype. But, I find their program to be a bit pricey. I bought several programs about five or six years ago, planning to use them when I retired. I have had no end of trouble with these. When I went to use them, I got a message that they were no longer supported and they wanted an outrageous fee to bring things up to date. I DO NOT recommend Rosetta Stone. There are many programs out there which are just as good, even better, for a much more reasonable price. I took two years of German in college and the German program from Rosetta Stone does not even come close to giving me anywhere close to what I would need to converse on a daily basis.
You can learn much with less levels, however, do not buy Rosetta Stone thru Amazon unless you are 100% positive you will keep it. I purchased levels 1-2 thru Amazon, liked the program, so month later i purchased the whole set thru Rosetta Stone & returned levels 1-2 to Amazon as I was told i could do but now......Amazon sent the product back to me informing they will not give refund because the software was opened. Unfortunately, at the cost of $300 (price of RS 1-2) i learned Amazon does not accept returns on opened software. I hope this helps....
Btw, Rosetta Stone customer service & tech support (including online chat) are available during normal business hours only.