Beersmith or Promash - it doesn't matter squat - YOU brew the beer not the program. It is MERELY a tool. A number cruncher and a database, that's all.
Interestingly most (OK, all I have met) professional (who truly do it and only IT for a living) microbrewers use Promash. (please excuse all the brackets). (Sorry).
Why?
Could be familiarity - what is the norm in the past/pretty well bombproof/if it ain't broke don't fix it.
Could be that because the Men In Black in Excise (If you've been been visited by them you'll know exactly what I mean) are happy with Promash as an approved suitable data management system from an excise perspective, naturally you would have all this data stored in hard/paper Excise approved format (of course, we dare not think otherwise).
Don't use it just because the pro's do, though.
When discussing brew ideas, pretty well all experienced microbrewers I have been fortunate to have met can do a lot of the calcs to a reasonable standard in their remaining brain cell anyway.
If it records what you did, lets you plan what you want to do, and keeps a track of what you have in stock, then use it.
MOST importantly, use it to improve your beer, to be consistent, to approach things analytically, not just 'Hey, lets try this for ***** and giggles this time'.
Even more importantly, if you are going to swing by the Steam Exchange, drop off a stubby - down here we get heaps of old codgers telling us how fantastic their beers are (apparently you can use a kilo of home brand sugar instead of the official CSR stuff, and its just as good :huh: ), but aren't willing to actually give us a sample...
Cheers & Beers