Our 4 month old has been a pretty good sleeper since about 3 weeks of age. Since that time, she routinely sleeps 7-8 hours at a time, occasionally waking up in the 2 AM range for a bottle.
We do that 'dream feed' thing or whatever the dumb buzz phrase is where we put her down at 7:30-ish, get her back up carefully at around 9 PM while she is still mostly asleep, give her a bottle, then put her back to bed. Puts her in a coma more times than not.
Since she's started teething and going through an obvious growth spurt plus natural sleep pattern changes, she's becoming a little bit more unpredictable. Has parties by herself in her room at whatever hour but typically puts herself back to sleep. We feel lucky as hell with the sleep aspect but know it could all go downhill fast any time now.