I played a bit with my new DTB-H260F last night and this morning, and so far my impressions are mostly favorable.
I use OTA only, with a large combination VHF/UHF antenna and rotator on the roof. I'm in a rural area at the south end of the Greenville SC DMA. I can also receive stations from Charlotte, Columbia and Augusta with varying degrees of success. Most of the Greenville stations (40-80 miles away) come in fine with my other DTV receivers, but a couple are problematical because of co-channel interference from analog stations in Columbia. In general, the Greenville stations benefit by being up in the NC mountains. I think I have line-of-sight to all of them. Stations from the other cities (65+ miles) don't have that elevation advantage, and the intervening terrain blocks the line of sight to some extent, but I can still receive several Charlotte and Columbia stations pretty well, with the others being intermittent.
I don't think I have major multipath problems, except maybe for my neighbors' large trees which tower over the back of my suburban-type property. My issues are mainly distance, lack of line-of-sight, and co-channel interference.
So far, the DTB-H260F seems to hold onto weak signals somewhat better than the two receivers that I'm comparing it with now: the US Digital from Wal-Mart and the Sony DHG-HDD500 DVR. I've noticed this particularly with one station that doesn't have co-channel interference (WACH-DT in Columbia) and one that does (WUNF-DT in Asheville). In both cases I've been able to get a steady picture on the DTB-H260F when the others either showed no picture at all or had frequent breakups.
The 10-bar signal meter behaves differently from my other STBs, in that I can get at least some picture across the entire range. Even when the meter reads 1-2 bars I can usually get a picture with occasional breakups. The picture usually doesn't disappear completely until the meter drops to 0 to 1 bar. With most signal meters, the picture disappears around 60% to 65%.
A channel scan always wipes out the previous channel list. There's no "additional scan" option. You can scan individual channels by entering the RF channel number in normal operation, provided that the channel number doesn't exist as a virtual channel number already. This means you have to be careful about the sequence in which you add channels. For example, if I've already scanned WOLO-DT (virtual 25, RF 8) in Columbia, I can't add WUNF-DT (virtual 33, RF 25) in Asheville because entering 25 takes me to WOLO-DT.
Like with the predecessor SIR-T451, the aspect ratio setting isn't stored on a per-channel basis. So if I set it to "pillarbox" for an SD channel or subchannel, I have to set it back to "full" when I change to an HD channel.
The 15-second bootup time is slightly annoying, because I've gottten spoiled by units that stay in standby mode when turned off.