The Snap and Seal system, and others like it, are good for outside work but still require a sealing ring on the port before you screw on the connector. The connectors are comparatively expensive and not well suited to indoor installations. So, if you are a cable company and most of your connectors are outdoors this is for you.

I have only used hex crimp connectors and a Cable Prep crimper even when I was doing CATV work. The standard method of weather proofing connectors is a rubber or plastic "spark plug cable" boot filled with silicone grease and slid over the connector and port. Never had a problem with outdoor fittings made up this way even 10 or more years later.

I noticed the splitters at my supply house are 900MHZ, while the ones the cable company uses are 1000MHZ. Is there much of a difference in performance?

If the CATV system you are tied to only goes to 750Mhz (as many do) obviously a splitter that will work up to 900Mhz is just fine- and then some. On the other hand if the system goes to 1000Mhz and you are using 900Mhz splitters there could be some additional attenuation in that last 100Mhz, maybe, maybe not depending on how good the splitter is. Will it be noticable? Probably not but the practice is to use passives that are designed for at least the highest frequency that must be handled. 1000Mhz passives are standard these days for CATV, 2050Mhz for DBS and satellite.

Do we really need a fancy crimper or are the regular 'twist-on' RG-6 connectors I use good enough?

To put it simply the twist-on connectors are for DIY's.

-Hal