Had excellent advice & help on this product, & alternatives, from Chris at FLO.
The RACI Finderscope is a pretty good product & certainly makes it easier, & less painful on the back, to locate objects high in the sky. Aligning the Finderscope can be a bit tricky & many reviewers have had problems keeping the Finderscope aligned, especially when the telescope is moved. However FLO provided a link to helpful advice on how to stabilise the alignment.
I would probably give the product 5* if Celestron weren't so penny pinching & lacking in customer focus. The Finderscope is a complex piece of equipment but comes with no instructions apart from advice on batteries. Also, batteries aren't included (it requires an unusual size) & there are no bolts to attach the Finderscope to the Celestron telescope (this replaced a defective red dot finder but the bolts for that were too short for this RACI Finderscope). It seems inexplicable to me that Celestron Finderscope for a Celestron telescope requires the customer to go to the effort & cost of sourcing additional parts! Therefore only 1* for Celestron.

I got this to augment the basic dot finder sight on my Celestron 8SE. I chose it over some cheaper options after advice from FLO, who pointed out the extra things it came with, namely a bracket that made it ready to fit to my scope and the illuminator. The bracket would be essential and the illuminator which is really quite useful. I'd already decided I needed a diagonal, after getting fed up of cricking my neck to look through the sight.
On the downside, there are no installation instructions other than how to put the batteries in, and you need to pay attention to everything stays screwed together. Otherwise, the Optics seem of good quality, and the boost in light gathering and magnification it brings seems to be well judged, with a good field of view.

Excelent service from FLO. Scope centreing is rather stiff and easily loses centreing location, if rough handled. Need to investigate spring loading.

I got this as a replacement for the little finder that came with my 9.25 Celestron SCT (Shame such a good scope comes with a such a limited finder). Anyway, the RACI is very easy to fit, took a couple of minutes to screw to new small dovetail to the scope. Optically the finder is really good and the adjustable illumination is excellent. I have found just a couple of small points to note. Adjusting the alignment of the finder to the scope is easy enough - two adjustable screws working against a spring loaded screw. But I find that the adjustable screws are pretty loose, and don't hold the finder very tightly so is very easy to loose alignment. I will have to see if the spring loaded screw can be adjusted itself so everything is held more firmly. Secondly it seems difficult to secure the right angle in one place - the securing thumb screws don't hold it well. But a bit of practice may sort that out. All in all, though, am happy with the finder.

Good finder. Tricky to fit to my c8. God views though. Worth the upgrade from the 6 X 30 standard finder.

This is very neat well made unit that is easy to use with very clear optics
Excellent service from FLO