The Pro-107 has the 'advantage' of having the RadioReference frequency database available on an SD card inserted in the scanner. You'd set up what you want to listen to by creating playlists from the available frequencies/systems on the database. The scanner comes with software to do that, and, from what I've read, database updates are also included. The disadvantage (to me at least) would be the lack of a keyboard. Everything is done via menu choices like in a media player.
The Pro-164 has the advantage of a keyboard, and if you purchase software & a programming cable, you would be able to tailor your selections to your personal taste a little more closely. (That's only a guess, as I don't own either scanner. Most users that have purchased the Pro-107 seem to like it, but it is aimed at an entry level scanner user, not the 'more advanced' users who want more control.)
Disadvantage for both of these scanners (over the next few years)- While both will monitor the current, main, HCRRS analog system, neither can monitor the newer HCRRS P25 (digital) system. The newer system will, apparently, eventually replace the analog system. Also, Houston (city) may also migrate to a digital system of their own in the next few years. There'll still be much to listen to, but certain specific cities & agencies may no longer be covered by either of these scanners.
So, 'get your feet wet' scanning with either of these units. If you enjoy it, then decide if you want to upgrade to digital when the systems convert in a few years, or add an additional scanner for them. Don't forget the audio feeds that may be available as well.
in addition to hiegtx's comments, the 160 will not do 7.5/6.25khz narrow band stepping on VHF, it want to round out the frequency. Programming the radio with Butel's software really bites also. Butel left so much out of their over priced software. The 160 has scan lists (What a Joke compared to the 107's play lists) The 107 does EDACS Wide & Narrow, the 160, only wide.
Yeah, if you can go back and swap the 160 for the 107 you'll be MUCH happier. But you'll be Even more happy if you swap the 160 and pay the extra and get a Pro-106!