Post pregnancy exercise

I wrote recently about what I was doing to regain my pre pregnancy fitness...  

One of the things I have taken to in a big way is swimming. I try and go three times a week, and I find the time in the pool is not only a brilliant, gentle exercise but also a great way for me to clear my head of the days' events.

I was also doing a bit of running, but found that my joints (particularly my hips and pelvis) were getting quite achey, so I have decided to scale that back a little at the moment, until I am around six months post partum.

I find swimming a really therapeutic form of exercise.... and also a great way to push myself harder. I am working hard to refine my swimming technique and to also increase the distance I am swimming - I have already increased noticeably from when I first started swimming regularly. However, in recent weeks I seem to have plateaued, and can't seem to get past the distance I am managing in each session.

With that in mind I am thinking of getting some sort of gadget to monitor my swimming. Any recommendations? 

What other gadgets do you use to keep in shape? I have heard of the Jawbone Up and fitbit - but are they any good? I'd love to know the thoughts of any other bloggers who use these - and do they make a difference?