It is a pretty expensive conversion, so take that into account when choosing a bike. You might be better off to buy a bike that already has them (brifters). Personally, I do not like bar ends at all. I don't mind down tube shifters as much.

Some people like bar ends a lot so it might be worth trying them. For me bar ends are not any more convenient than down tube shifters and they tend to be knee bangers. Also they always seem to be getting bumped out of gear when the bike is leaned against something.