I don't own a set of Golds but I've tried both Clapton and Buddy Guy Strats that were fitted with Gold Sensors and the Fender Mid-Boost Kit and I agree with bobbya's description,
They are a bit glassy and compressed-sounding
That was until I got the mid boost on about 8. Along with a welcome boost in the mids and the output, it thickened the bottom end (just enough), increased the sustain and brought out a really nice bite the bridge and middle pups.
I do however, own a set of Lace Colours (Red, Silver, Blue). I've been banging on about how great these pups are quite a bit on these forums so I'll keep this short. They're great all round pups and my personal favourite at the mo!
As far as a comparison goes, the colours have much more output and tonal variance than golds IMO.
Lace get some pretty rough reviews especially when compared to traditional or “true” single coils. If I was after a traditional strat tone, I wouldn't buy or recommend Lace Sensors as they are a very contemporary sounding pups. I have no experience of the Fat 50's but I'd bet money they'll sound very different from the Golds simply by the vast difference in design. The 50's won't have that Hi-Fi compressed tone that's so dominant in the Golds and will probably have a greater dynamic response to different playing / picking styles. For example; you'll notice a greater difference in tone between playing hard or soft with the 50's.
Slightly off topic......
I also own a set of Hot Golds and feel that Lace have produced a winning pup here. They have retained all the good aspects of the original Gold sensor and given them a some balls! IMO much more versatile and slightly more “real / true sounding ” than the originals. My set has the 13.2k bridge pup which despite being double the resistance is still (to my ears) very well balanced with the other two pups. They're wired up to the Fender S-1 switch and the Clapton Mid Boost kit (there's a thread for how to do this). All-in-all a winning combination in my book.
I'd put the Hot Golds in-between the Golds and the Colours as far as tone and output go.
Hope this helps