The best replacement for 510 is ego.

The best alternatives to 510 are rated as following:
★★★★★  ego
★★★★  808
★★★★  511
★★★  901
★★★  810
★★  510-t
★★  511 levis
★★  306
★★  kr808
★★  ego threads
★  810 garmin
★  306 atomizer
★  801
★  520
★  240z
★  901 atomizer
★  910
  500
  bmw 2002
  eroll
  blu
  901 atty
  canon sx40
  mx 518
  dsm 520
  510
  voyager 520
  kr808d
  tomtom one
  dse 901
  610
  ego battery
  ktm 525
  voyager pro
  tornado
  900
  ego thread
  blueant q2

Your alternative for 510 is not listed? Suggest!
Speaking about 510, one probably shouldn't forget about ego battery.

Other search terms related to 510 and their ratings are:
★★★★★ ego battery
★ strava
You have in mind a companion for 510 and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of 510 in all years. Click on graph for more.
510
ego
808