We operate panels in many practice areas and in many countries. We don't always have a practice area specialist who knows firms in the country, so that is where guides like this come in handy.
The IFLR1000 is a useful cross reference to refer to ... to make sure a personal referral aligns with some objective rankings from a survey. I would refer to it in my main area, M&A, when looking for a counsel in a country we are new to.
The country-by-country tiered rankings by practice area are a good approach, to get a rough feel if a firm is viewed as active in a practice area.
UK General Counsel
US-listed multi-national corporate
I find the IFLR1000 an up-to-date and credible source for selecting and sourcing new legal firms in a new business area or country, and to compare legal firms capabilities in different practices.
I find the tiered rankings particularly useful when benchmarking and comparing between existing legal firms, plus looking at unfamiliar legal practices or locations.