I know this is going to sound mean, but you really don't get much of a road bike for around £350 (or less)
But I do know not everyone can justify £2000 and therefore cut their cloth to suit.
A bike like those mentioned here so often, will do a job, for a while but even with care and regular maintenance its not long before 'wear and tear' becomes 'worn out and broken', this is in addition to the poor ride and performance from new
So what am I saying exactly, well I read time and again on here similar questions, "is it a good bike", No.
Of course it gets people out & riding and that's not a bad thing, but I regularly see these bikes deteriorate to a point were it cant be much fun to ride, and at worst unsafe.
Also, you have a situation were if money is spent on it to maintain it, you now have a £300 bike that's cost you, say another £150 +, that's on top of any general running costs that any bike will incur.
Use them as a stepping stone, If you ride more, find a way to something worthwhile.
I am sure there will be those lining up to contradict me, some rightly will comment that they don't expect a quality performance etc, but it fits their budget, that's fine, go for it.
But remember that the upgrade in quality,features & function of a £500 model is going to cost you double the price difference if you decide to upgrade the bike yourself at a later date.