As with everything do plenty of research and make sure your diet is on point.
Have done a cycle of ostarine (25mg/day) + cardarine (20mg/day) for 12 weeks - felt good; really reduced soreness, better recovery, improved concentration/mindset while training. It definitely helped with an ongoing elbow injury - no problems with heavy lifting at all. Not sure if it did anything in terms of muscle building but I didn't lose muscle while losing weight which was my main goal so I'm sold on its anti-catabolic properties and supposedly helps with endurance/stamina and I was doing a lot of cardio so makes sense.
Also started a Ligandrol (LGD) (10mg/day) stack with the above but stopped after 5 weeks due to suppression issues (very low libido) and also on non-training days felt very 'wired' and apprehensive (almost like MDMA without the good vibes). LGD is the shit tho when it comes to strength - literally smashing my then PBs with ease and felt very in the zone so it definitely works. Gave me mad confidence and concentration while training. Put on mass as well (and on maintenance calories or thereabouts), had a very 'swole' look but in my mind not worth it for the sides (tho 5mg/day may be better).
I've never done proper gear so can't advise in terms of how they compare but would definitely do the osta/cardarine stack again. PCT was enclomiphene (from the same supplier) plus an OTC enti-estro and HCG generate (expensive and not sure it was worth it). Would probably do a proper clomid/nolva next time tbh.
Would also second receptorchem.co.uk - where I got mine from. Stay away from pills/powders - liquid is the proper stuff (tastes terrible tho).