It's been available for Mac for a while now, and many say it's a good alternative to Ps.

I don't have ready access to a Mac to know this, and don't use Ps to know that either, but I downloaded the Affinity beta and it seems ok, except for a few missing vitals(but remembering that I'm pretty a-retettive when it comes to what software should and shouldn't do.

First up I can't see any easy way to just browse.
That is, like the film strip in CaptureOne, and or ViewNX2 .. where you just browse to a folder location and pick and choose images at will.

My retentiveness literally means that I can't bring myself to commit to Lr due to it's idiotic "import" routine.

Sometimes I'm just bored and want to open an image and just tinker .. I don't want to spend 5 months importing stuff(and for similar reasons, why my business interests never ever extended into the importing genre! )

.. anyhow rant over, back onto Affinity.

It's currently free to download and use the public beta.
On the whole, it's v.easy to use .. just some cryptic and arcane placement of tools and processes.

Then again I'm the type of image editing type that just wants one tool to do every thing .. ala CaptureNXs colour control points, and then press Cntrl-S to save and Cntrl-Shift-S to save as.

I couldn't every in 4 billion years get used to LRs cntrl-E siliness .. unless all other software switched to Cntrl-E to save stuff too.(just silly habits I guess)

.. anyhow, rant over once again.

So it took me 3 attempts at one image going over it again and again until I found a way to save in Affinity.
I then pressed ahead in my usual manner and pressed as many button combinations and slid as many sliders as I could until smoke billowed out!
Luckily no smoke .. as it's hard enough trying to convince myself it's time to quit one day .. soon .. maybe! I didn't need any more smoke(and besides, this PC is new and I don't[yet] want to smoke it!)

Speed is overall quite 'acceptable'.
Edits are overall quick, but the only concern is initial image rendering.
On any image I haven't yet opened, I'm waiting about 20-ish(+) secs for it to render on screen, once you hit the open button.
That in itself isn't the only issue. the real issue is that there is no indication that you actually just did so .. so you may think ... oh, my mouse click didn't take or something.
It did, just don't do it again while it's processing or you risk crashing or a not responding msg.
They could add a animated icon to allay confusion(and crashing).
FWIW: same images coming off the same SSD(which is very fast!) load in about 1/2 sec on VNX2(which is supposed to be slow) and overall just quick in all other image browsing software.

side note: one of my reasons for having FSViewer always installed on my PCs is that it's always been super lightning quick to load images. But so far on this PC, it's been slow-ish.
PC specs have octupled over my last PC mainly in terms of RAM and drive speeds(SSDs) .. but FSViewer has responded in kind .. whereas both VNX2 and CNX2 both have.
Have yet to try Lr again(and no hurry too either). And Photo Gallery which was suicide inducing is much improved, although still slow-ish.
I'm hoping that the slowness is just a beta thing and in combination with large 90Meg D800 files too.

So for a bit of fun, whilst pushing as many buttons and sliding as many slidey looking things as I could I have two images to show you as results(from a Ps dunce such as myself):

D800E_DSD_1687_sml.jpg
I used FSViewer to resize, but edits were basic and simple(exposure/tone/clarity/detail/type stuff) and also a vignette to see how that worked as well.

2 mins later, after pushing some buttons and then sliding stuff around:
D800E_DSD_1687_liquified_sml.jpg

As said above, I'm a Ps dunce, and it once took me nearly an entire day to realise that I had no way of editing a PNG file for my sisters cafe logo.
I then opened the PNG file in PaintDotNet and had it all done(layers and transformations) in about an hour after two to and fros between us over emails.
*** The point here is that I just can't get PhotoShops workflow through to my vast empty head, yet I can use other software quite easily!

Same goes here in Affinity .. push a button, find some tool to play with and play away ..

Important note tho: As I'm still stuck in the dark ages of expired Nikon specific software: I really only compare to what I'm used too.
So far(in about 6 attempts at different settings) .. I can't get anywhere near the same detail quality from Affinity as I can easily get in VNX2.
Then again I always had the same issue in LR3 and 4 too. Briefly tried Lr5 as a trial, and gave it away just before it expired.

I reckon it's worth a try! remember it's free, I reckon a few Mac users out there probably using it already

.. and Andrew! if you're reading this and haven't yet tried it, I reckon it may be worth a try.