Just bought a Dell Axim 50v and BT-338, using GPX sonar and GPX tuner. Quite nice, though I have a few issues.
Also have a Etrex Legend, but a crack on the screen (loosing about 25% of the display) initated the replament.
While the BT-338 is very quick to lock on, there are a number of things I prefered the about the Garmin.
1. So far I havn't managed to figure out how to change the update frequency for the BT-338, and every 4-5 secs just isn't as nice as the every second or 2 that the Etrex used to mannage.
2. The PDA hold loads of data, however it probably takes me 5 minites to get everything set up ready to go.
3. I found with the Etrex I could usually find a cache without the clues, now I seem to be more dependent on them.
I do however enjoy the extra options having hte PDA give me.