Montane featherlite marathon jacket review

Here's an early first few impressions of a jacket I recently bought.  To be honest I'm a little disappointed in the jacket and in myself for buying it.  I bought it on impulse: something I only very rarely do.  I was after a lightweight dual purpose jacket I could use for running and use on the bike.

Plus points:

• really bright day-glow yellow, with a reflective trim
• just £45 (and perhaps this is where the problem lies)
• complete with a really useful stuff sack which is well made and has a useful Velcro strap
• nice slim fit but as it is not cycle specific the tail doesn't come down too far
• the elasticated sleeves are long enough for cycling
• very light; the label says <150g / 5oz for the medium size

So what am I about to whine about?  Well, it doesn't seem very breathable.  One day I rode to work and worked hard keeping up a brisk pace and I was wearing a cotton polo shirt underneath.  The sweat was "significant" and once again I'm thankful to have an office for myself.  On thinking the polo short caused the problem, I wore a couple of thin wicking layers and the problem persisted, although less so.  Perhaps I'm asking too much of a basic jacket? On a practical note, there's not one pocket.

These are my first impressions and I haven't even used it for running so I might need to update it later.  I'm not impressed, I wish I'd done some research and got something better.

Related:
My cycling in the rain guide