Regarding price...
The 396XT retails for around $450 new, but it includes a data cable, batteries, and programming software is free.
The Pro-106 retails for around $400 new (currently on sale for $349), but does NOT include a data cable ($30) or batteries ($10), and programming software costs at least $35. Even at the current sale price it ends up costing around about the same as a 396XT (when not on sale it ends up costing more).
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Regarding features/function/form...
The 396XT is much smaller and has a more "solid" build quality than the Pro-106. It has a multi-color backlit LCD panel (and you can assign different colors to individual channels). The small size comes at the price of less buttons and a combined volume/squelch/scroll/select knob (adjusting volume is a bit irritating as you must first press down on the knob before rotating it, very poor design IMO). Almost every key on the front panel has a secondary function which is used with the FUNC modifier key on the side of the scanner. Many people complain about poor P25/digital decoding/audio quality with the 396XT, but in my opinion it does just fine. The 396XT uses Uniden's DMA memory system which is very flexible and easier to understand for those who are only used to the traditional fixed bank/channel system used on older (and cheaper) scanners.
The Pro-106 is much larger and does not feel as [physically] well made as the 396XT. It has only a plain-jane amber color backlit LCD panel, but it does include a multi-color LED light on the front which is user-adjustable. It has many more keys and uses traditional (separate) volume and squelch controls. Many people say that the Pro-106 has better P25/digital audio decoding and louder audio than the 396XT. The Pro-106 uses GRE's OOM / V-scanner memory system which is much better than banks/channels, but is limited in flexibility and "simultaneously usable" memory space when compared to Uniden's DMA memory system. It has a lot of memory space but that space is divided into 21 equally sized V-scanners, and unfortunately you can only scan 1 on them at a time. In my opinion, this severely limits what would otherwise be a very good memory system.
Hope that helps. Whichever model you choose, good luck and happy scanning
