I have had two years as a SAHM, went back to work recently (new job, same industry) for 4 days a week.
I didn't need to go back to work financially, it was a decision I made as I wasn't 100% happy being at home all the time (household chores are not my forte). I missed my freedom (yes, I know that comes with being a parent, but not even being able to go to the toilet on your own does become tedious), missed regular contact with people (I did make friends while on mat leave but the majority have gone back to work full- or almost full-time) and wanted to feel more equal within my relationship.
I thought I would relish being a SAHM and thought I would never want to come back to work. But after two years I realised it wasn't as easy being at home as I thought (!!) and that in fact, some time spent away from home would actually be beneficial to all of us. Our child has gone to a childminder three days a week (husband also takes a day off in week) which provides a homely setting for him and overall we've had no real problems with him settling in. He has gained new skills and confidence from spending more time around other children. I do sometimes feel guilty though for 'choosing' work over being at home but hey, being a parent is laced with guilt whatever you do or don't do.
I am pretty confident I made the right choice for me, coming back to work, but am now considering changing jobs to something with fewer hours or even starting something up on my own that's more flexible. I have been given 'free reign' by DH on what I want to do, so long as we're not massively out of pocket, and find myself asking what I REALLY want to do with my life.... my job is enjoyable but usual office politics etc bore me to tears sometimes. And when DS is being lovely I regret coming to work. But sometimes when he's being....testing....I am relieved I get a good break away.
I second the previous poster who suggested maybe going back to work, part time if you can manage, and THEN make a decision after experiencing both.
Being back at work isn't the same as before though, I can never stay to after work drinks as I have to dash for the childminder. But I have made some nice friends who have similar interests (not just people who happen to be parents to children of roughly the same age....nice enough as they are, most of my 'mum' friends I don't actually have much in common with).
I do feel more confident in myself being back at work. I am good at what I do. People ask my opinions on things. I produce tangible results. Parenting is never-ending, no real results, very fluid, and I found it absolutely knackering. The logistics now of childminder pick up/collection is a bit of a pain, but overall I think it's worth it. At the end of every month we aren't that much better off by me being back at work, my salary pays for childcare with around £200 extra each month most of which i spend on nice lunches during my break but it's about more than the money to me. I feel more like me again.
Hope that bit of insight helps a bit