Me (I'm pregnant), my husband (had to pay at Boots) and my 4 year old son (had nasal spray at GP surgery) all had it this year.
None of us suffered a single side effect (I think my arm might have been a little bit sore the next day maybe) and despite a lot of flu circulating around our local area, none of us have caught it and friends in other parts of the country have reported the same and are glad they had it. There's no way of knowing if it has actually prevented anything as maybe we were never destined to get the flu this winter anyway, but it was definitely worth the risk.
With the nasal vaccine, because it is a live vaccine (unlike the jab) there is a risk that the child might feel a bit under the weather for a few days. My son never has and I've never heard a friend report any side effects either.
With hindsight, I'm really glad we decided to all do it this year and will be doing the same next year.
The problem is, people get a nasty cold that really knocks them for six but ultimately is not too debilitating and they think they have had the flu so they label vaccination as being unnecessary. Genuine flu is when you are confined to bed for two weeks, couldn't even face lifting your head off the pillow to pick up a £50 note off the floor and may even end up hospitalised. Flu routinely kills the very old, the infirm and the very young. It nearly killed a baby in our village who was already poorly - he was in paediatric intensive care for several weeks. Even though my four year old is pretty robust, I would be really quite scared if he caught proper flu.
Flu is a big deal. Even if you are perfectly healthy, the less flu circulating around the better and even though the flu vaccine doesn't work in many cases, every little helps.