We've only brewed a half dozen batches, so for whatever its worth... but I used BRY-97 for all of our initial beers. Coming to a new system, a new scale, at times new ingredients, etc. I wanted to eliminate as many variables as possible, so the ease of using dry yeast was hard to pass up. For our British/session beers, we are using the Timothy Taylor yeast from BSI.
I'm subject to the same limitations that majorvices mentioned. I could decide to just brew something using a random yeast but a pitch of yeast isn't cheap so it has to be used on an entire series of beers to really fit into the budget. One brick of BRY-97 was about $150 and had enough yeast to be directly pitched into two batches (one 12P, one 17P). The only way to make that more economical is to re-use the yeast.
Keeping a pitchable quantity of the yeast in good condition is another trick. If you switch yeasts mid-stream, your original yeast may sit around for a week or two and lose viability. Right now, I don't really have a good setup for a yeast brink and so I've just been trying to keep the yeast going with new batches of beer.
I will likely switch away from BRY-97 once I have a good handle on all the other things there are to worry about. Ultimately, if you're starting out with fewer than 3 or 4 fermenters, you will need to pick a yeast that is versatile. Something that will flocculate out either with or without some fining encouragement.
I don't know that specifically being familiar with a strain is a pre-requisite as long as the strain is consistently well-reviewed. You will become familiar with the strain within a couple batches as long as you keep decent notes, follow the same temperature regimen, etc.