The wonderful lake in the middle of the park is the main focal point and there are lots of different routes you can take around it for nice walks for couples and families. Definitely still worth the trip during the week.

However, unless you enjoy feeling like an unwelcome minority in your own country, I would recommend avoiding the park on weekends in summer, as it is absolutely swarming with Turkish people having barbecues and playing loud Turkish music from their car stereos. It's not just one group either, it's an entire village worth of very loud immigrants shouting everywhere, dancing to the pumping music and all with smoky barbecues. This is now the 3rd Sunday walk in as many months ruined by these people who have clearly no respect for the park or the local people who frequent it. The complete opposite of a peaceful walk by the lake.

Edit: Having been regularly when it's not hot weather, it's a beautiful place for the majority of the year. So I think 4 stars is now a fairer assessment. Would be 5 stars if they did something about the immigrants with barbecues and loud music over the summer months.