The best replacement for softphone is hardphone.

The best alternatives to softphone are rated as following:
★★★★★  hardphone
★★★  groundwire
★★  hard phone
★★  ip phone
★  ip communicator
★  bria
★  clearsea

Your alternative for softphone is not listed? Suggest!
Speaking about softphone, one probably shouldn't forget about g729 codec.

Other search terms related to softphone and their ratings are:
★★★★★ g729 codec
★★★ vonage
lingo
You have in mind a companion for softphone and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of softphone in all years. Click on graph for more.
softphone
hardphone
groundwire