It's different for everyone, OP.
There are a lot of different ads and everyone reacts to them differently. If you try one and it doesn't work, change it.
Fwiw I spent some time on citalopram, and yes, the highs weren't as high and the lows weren't as low. That was exactly what I needed at the time.
The grief exception - are you expecting a bereavement to occur soon or has it already happened? Do/did you already have a difficulty with mood before this? Some professionals consider the first 6 months after a loss to be grieving, and might be reluctant to prescribe medication for a "natural" state of being (but ime most GPs are very willing to prescribe).
Will it bite you on the bum later? I'm not 100% what you're asking here, but if it's "Will all the grief come flooding back when I stop taking them?" then the answer will be (sorry) "It depends".
Usually, when people stop taking ads, they do experience a period of low or changeable moods. For this reason, it's important to be sure and ready when it's time to stop taking them. Generally, 6 months is a pretty short time to be taking ads.
Research consistently shows best recovery rates happen when ads are taken alongside a talking therapy, not just one or the other.
There's a great book called Malignant Sadness by Lewis Wolpert about depression.
A big one often brushed under the carpet are sexual side effects
Although lots of people on anti depressants do report a loss of libido, it's worth remembering that depression itself causes this too. Sometimes it's not clear whether the symptom is caused by the drug or by the illness. I found ads actually helped in this department, by making me less depressed.
It's really important to remember that ads are a tool that can help us overcome depression, but not a magic bullet. They typically take a few weeks to start to work and can make us feel worse before we feel better.