I recently picked up a Mohu Leaf Antenna in hopes of picking up all my local channels in HD. Since I don't live terribly far from any of the towers, I am able to pick up NBC, ABC, Fox, CW, and CBS in crystal clear HD for free. I really don't like don't paying $75 a month for cable when 95% of the shows we watch come on one of the major networks. I had forgotten about the option of using it with a TiVo until my wife asked if there was a way we could record from the antenna.
Before I purchased one, I researched to see if there was anything better on the market and TiVo still seems like the best alternative for TV-based standalone DVRs. I went with the $199 model (and $14.99 per month) as it's the only one that supports an antenna. I actually have a long history with TiVo. In fact, I used a TiVo from 2003 to 2006. I had a Series 2 TiVo with the lifetime service. I was a TiVo evangelist if there every was one. During the short lived TiVo Rewards Program, I got enough points to get 2 iPods (the HP co-branded ones). Once I upgraded to an HDTV, I had to leave my trusty TiVo behind and switch to a cable company DVR. It was relegated to the bedroom for a while and I eventually sold it on eBay (the lifetime service retains its value quite nicely). I haven't kept up with TiVo since (other than listening to John Siracusa complain about it).
I picked it up at Best Buy (they had 3 in stock). Opening the box revealed a much smaller device than I remembered (it's been years since I last used one). I quickly got it hooked up to my TV and started the setup process. I was expecting a 10-15 minute process, but it took my nearly 1.5 hours. It seemed like it was upgrade, reboot, click a few button, upgrade, and reboot again. I had trouble getting it on my network (on WiFi or ethernet) initially, but it finally connected with ethernet (WiFi worked as soon as I unplugged ethernet outside of the setup screen). It seems to be staying connected with no other issues. Although it took little longer than I expected, I had finally got the TiVo setup.
The actual functionally of TiVo is fantastic. It's drastically easier to use than any other DVR on the market. There are iOS apps that allow you to schedule shows, change the channel, and stream live TV (on the higher end models). The main complaint I have so far (outside of a clunky setup process) is that not all of the menus are HD. The main ones are in HD, but a lot of the secondary ones have an awkward transition to SD. Overall, if you are looking to get started with an antenna and a standalone DVR, I recommend both the Leaf antenna and a TiVo Roamio.