I'm using...
IGPSport IGS50E
https://www.igpsport.com/bike-computersI've used this for about 2 years now. I'm not exactly someone who uses the data to plot out some scheduling for rides or to monitor my exercise or something. So this is simple and more than sufficient for my use.
And Magene H64 Heart Rate Monitor
Only been using this since Sep or Oct. 2020. I only use it as a warning device not to hit a certain heart rate. If I see I'm approaching that figure, I simply shift down to an easier gear or take a rest.
Both devices connects seamlessly with each other.
How accurate are they? To be honest, I don't know. The IGPSport is consistently recording shorter distances (just a small fraction) compared to my Sony Experia cp running Relive. But viewing all those YouTube videos reviews or bikepackers about their cyclocomputers and cp apps, everyone is saying none of their apps/devices showed the same data. Suppose to be I can choose to connect Relive with a cyclocomputer but I just never tried to. No particular reasons, I just use them simultaneously but independently. My phone (with Relive app) is usually in my pocket. The iGPSport is visible on the handlebar. Here's a sample data of both device, same trip. These are the key differences.
iGPSport Relive
Distance 16.9km 17.3km
Max Speed 29.4kph 38.2kph
Ave. Speed 15.3kph 12.1kph
AST 52m 283m
Time moving trip duration
Distance: iGPSport always came shorter than Relive. It doesn't bother me much.
Speed: This really bugged me. The difference is quite significant. During rides, I follow iGPSport but when sharing my rides on FB it's the Relive video I use.
Elevation: iGPSport is the right one, I calibrated it but I never did calibrated my cellphone for elevation. So I'm inclined to believe that my Relive Speed might be affected (although unfounded).
I didn't bother with the time as they record it differently. The iGPSport records only moving time, while Relive records the entire trip (from pressing Start to pressing Finish button, I didn't set it to auto-pause). I do like to have both info.