The best replacement for picaxe is arduino.

The best alternatives to picaxe are rated as following:
★★★★★  arduino
★★★  pic
★★  basic stamp
★  microchip

Your alternative for picaxe is not listed? Suggest!
Speaking about picaxe, one probably shouldn't forget about i2c.

Other search terms related to picaxe and their ratings are:
★★★★★ i2c
You have in mind a companion for picaxe and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of picaxe in all years. Click on graph for more.
picaxe
arduino
pic