I do agree with alot of the comments, but also disagree at the same time. Wensum have always been rubbish with messages, and yes they don't seem to have professional handymen (more men with spanners who will give it a go). However, their customer service has possibly improved.
My accomodation was very clean when I first moved in, the rent very reasonable (the fees were stupid but unlike other agencies, wensum actually did take up all my references!). The lady next door slated them to me, saying there was damp and mould etc (which filled me with dread). However, I have been in my accomodation over a winter and don't have a problem (its a very cold accomodation and you must have the heating on or yes, damp would appear but isn't this the case in old properties?)
I tend to do small upkeeps myself (painting bathroom ceiling, painting over mouldy old grout etc), I did mention it to wensum but they did nothing whatsoever. However when things have properly broken (ie, boilers, electrical things), they have been pretty quick to fix and I have had no problems.
I had a hunch they would try to keep all my deposit when I move out, so I am staying here as long as possible because I have been scammed before.
Basically, I think that if you don't have high standards (and I don't because it's a cheap property in a bit of a rough area) then they aren't bad. I wouldn't recommend it, but then i can't think of any letting agency specialising in cheap properties that I would recommend!