I just got my first brifter equipped bikes this year, even though I've been riding over 50 years (since I got my first two wheeler at 4 years old).

First impressions? More convenient to shift, if you're one of the those riders that shifts constantly. If you shift less often and stay in a gear for a while? Less of a difference. In fact, I like the fact that the throws on downtube shifters are so short with index shifting. Barely a flick or movement, and clunk, you're in another gear. The travel movement of the brifter levers is much longer and shufting is slower in comparison to downtube mounted or stem mounted index shifting levers.

And what about costs. A set of used bifters with unknown service life remaining will cost you more than a complete, nice, used, steel or aluminum bike equipped with downtube shifters.

Shorter service life, more expensive, less reliable, and more maintenance. Broke a shifter cable, and now the shifter is totaled is a pretty common theme on BF and on the Internet. That's how I view brifters.

Riding a brifter bike is like driving a car with an automatic transmission. More convenient in traffic, less road feel for the driver. Takes some of the fun out of driving/riding.