I think you're going to find the Bridgeport Series I mills come in a variety of sizes and HP's. The smallest have 36" tables while the largest are 49". They also come in HP ranges from 3/4 to 3 depending on the year, table size and head configuration.
I have a 1972, 1.5 hp model with a 9" x 42" table and variable speed head. To me it's the most versatile of the bunch. It's large enough and powerful enough for most work. The variable speed head makes speed changes extremely easy. I do a lot of tapping so I continually change speeds between 1,200 and 70 rpm.
The most popular size Series I machine weighs in at about 2,100 lbs. depending on the accessories like power feed, power drawbar, DRO, etc. I disassembled mine and carried everything except the column to the basement shop with an appliance dolly. The dolly wasn't strong enough to move the column (1,000 lbs.). I tried renting or buying a 1,700 lb. capable stair climber dolly, but eventually hired a moving company with one to move the column. It took them all of 20 minutes and cost less than $200.00
If you insist on a smaller machine Burke makes on about 2/3 the size of a Bridgeport. I know several people who have them. If you only intend to do small work they may fit your bill. However due to their smaller size and lesser hp they are not suited for bigger jobs.
As an FYI mine came from a local high school. It still had the invoice in the column when I brought it home. With a vise, power feed, metric and imperial dials, and a set of collets the list price was just over $1,400.00.
Even the M heads were too high for me.
