These bulbs were hard to find at the time (2006) - an R40 flood CFL that was comparable to 75 watt incandescent... (Lowe's now carries a similar product). For the type of recessed can we have, the R40 works best by size. Par38 would fit. R30 would fit but look undersized... This CFL from TCP has good color and very good brightness (lumens) - I almost thought they were too bright compared to the incandescents they replaced, but the ultimate test of the "Wife" proved that they were fine. :)
Like other CFLs of this style, they do have a "warm up" time in which they are a bit dim. Takes some getting used to, but once you expect it - not that big a deal. Only takes around 30 or 40 seconds for them to get nice and bright... haven't actually timed that, but pretty close.
They do save a ton of energy. For example - in our hall we replaced all 3 75 watt incandescents with these. All 3 new bulbs use less energy than just one of the old (3 x 16 = 48 watts vs. 3 x 75 = 225 watts!!!). We have around 10 of them in our home and our electric bill definately reflects it!
Had them in since late 2006 - all still working great!