I wouldnt personally buy a z3 or z5 compact.
They're truly great featured phones but the z3 suffers constant screen & glass back breakages from out of nowhere & the z5 suffers overheating.
On a premium performance level the one plus one is still hard to beat at £199 retail , the one plus 2 is good but not worth the £50 premium.
Out of the fairly budget Chinese brands , the ulefone power , oppo find ,& especially the huawei p8 are very very good phones.
The p8 is on a par with the oneplus
The ulefone & oppo are mtk octacore chipsets & while great for general use the msli GPU on them struggles with 3d gaming at 1080p.
The ulefone is incredible value for £130 though & has a 6amp battery that can last for 3-4 days (it also charges from flat in around 2 hours)