I tried this against a Meade Super Plossl 15mm eyepiece. The performance on the lunar disk was very close (excellent) between the two eyepieces, but the BST StarGuider ED 15mm wins by a whisker due to the wider angle!

I am very happy with this eyepiece of 15mm. I had read a very good reports of this eyepiece and I have been able to verify these opinions. Vision is clear and sharp. The eye relief is great and very useful for people with glasses like me. It is a bit heavy but without problems for my small telescope Newton Orion 100 / 400. I am delighyted with this eyepiece. I will not hesitate to buy BST Starguider again in the future.

This is my first branded eyepiece so unfortunately I don't really have that much to compare it too. The build quality is obviously much better than the 2 eyepieces that came with my skywatcher 200p, the twist up eyecup is also really nice and feels like it'll last a lot longer than the flip up equivalents on the standard eyepieces. Image quality seems fine, feels about on par with my standard 25mm eyepiece, maybe slightly better, slightly larger FOV is also nice. Eye relief doesnt feel all that great compared to my 25mm, can be trickier to observe with. Observing bright objects can create a glare/reflection at certain angles which can be annoying.
Overall though i would say these eyepieces seem like they are worth thier price, although i probably wouldn't replace my standard eyepieces with BST equivalents, they are good cheap alternatives when it comes to buying eyepieces to fill the gaps in your collection.