To be fair to Lecroy, the stuff they are rebadging is generally some of the best of the "B brands"
Still 2x the cost though!
First of all, I wouldn´t call siglent (AND rigol) as B brands nowadays...These times are gone since they offer good stuff and not in every case cheap...

Then concerning the partnership between Lecroy and Siglent:
It was in the early 2010s a region lecroy sales engineer was on visit by us and we´ve talked about cheap scopes from lecroy.
The talk comes to the "desastrous" WaveAce series at this time.
He was really getting upset and shouted never ever we trust on any chinese company to make a deal with them!
And now..
Siglent make the Wavesurfer 3000Z and the Wavesurfer 4000HD scopes for them, lecroy take siglents SDS2000X+ and SDS1000X-E under their name..
Or like a engineer colleague said once to me, with the partnership to lecroy, siglent are the "kings" under the chinese brands.
Kings I wouldn´t say but you can recognize it when having a look to their touchscreen models 2000X+, 5000X, 2000x HD and 6000A.
They´re more lecroy style with all the pros and cons...
In my opinion a good way siglent are going.
If what Martin says is correct
It is, have a look at the spec sheets of the "lecroysiglent" ones...