I know men who use pills, the injections and have implants. These are some of their comments.
The men who use the pills have said that different meds react differently with each of them so that you need to try all of them before deciding that they don't work. They are dependent upon the man being aroused in the first place and can be unpredictable.
The men who use the injections have several comments.
1) original instructions for the injection was poorly done. If you miss the tube that the medication needs to be injected into the injection will not work. Once properly instructed they had no problems with the injection working.
2) they are dependent upon the man being aroused in the first place.
3.) If done correctly the erection can last up to 4 hours and the man can orgasm more than once during that time however not all of the orgasms will produce ejaculate.
4.)Some have incorporated the injection into foreplay
The men who have had implants also have several comments
1.) There is no question or doubt about having an erection. It is guaranteed.
2.) There is occasionally a loss of feeling in the penis meaning it takes much longer to achieve orgasm and at times they are unable to orgasm
3.) Several of the women have commented that while the erection is wonderful the men need to "pound away" at them in order to feel and/or orgasm.
4.) Once having an implant you can not have it reversed and if something happens (which it rarely does) that necessitates it's removal you can no longer get any type of erection
There are pros and cons for each of these and each should be weighed when making a decision.