I tecently bought a brand new 2017 GMC Sierra SLE with the Elevation package.
Black isn't the only colour it comes in anymore. I got the Stone Blue colour.
So far so good. I've now had it for two weeks and the fuel mileage isn't bad for what it is. The new 5.3 engine is totally redesigned from the previous generation 5.3. The active fuel management sure helps the mpg's. It's designed to make the engine operate as a four cylinder when cruising.
So far after about 300 miles I've averaged about 16.5 mpg doing about 60% city and 40% highway driving.
Not bad considering I've also had a 2.5" levelling kit installed on the front end and added Toyo all terrain 285/55/20 tires. I have the 3.42 axle ratio.

I guess the one I was behind the other day had blocks installed after he bought it

I hope you meant 25-30 ft range!!! You are going to need a Kenworth for a boat that size Not to mention all the over width permits

Any issues with the transmission shifting weird? I test drive a couple and can't get past the goofy shifting patterns and the cheap interior.

what goofy shifting pattern?

Opinions on interiors are like azz holes everyone has one. Every person thinks theirs is the best.

I can pick up any girly magazine and see that's not true.

I'm not Chevy bashing, I was planning on buying one. I've owned two Fords with the 3.5 ecoboost engines, the first one cost me almost 10k in repairs up to the point I sold it with 110k miles on it, and they just told me our explorer needs a new engine at 82k miles due to the oil not being changed often enough. I really wanted to like the Chevy. They have a very unusual shift from 1-2, 2-3, and 3-4 gears. The salesman tell me that it will get better with time, but who wants to roll the dice with $40k? Compared with Ford, Dodge, Nissan and Toyota the interior seems to be lower quality. Sorry if that offends you...

I'm ok with the interior.
I have the SLE model which is an improvement over the base model. It has some woodgrain panels on the door, aluminum accent trim over the vents and radio surround and accent stitching on the dash and seats.
The ugly interior may have been that of the base model.
Either way it's all personal choice. I know people with BMW's who say their interior is so gorgeous and they hate my interior. I sit in their BMW and I hate the interior.
Personal choice.....

Just sold my 2007 GMC Sierra with 139000 miles. In last 3 months, repaired water pump, transmission cooler lines, alternator, starter and then the transmission started acting up.

Every GM I've had required new transmissions at 125000 to 140000 miles. I'm done with GMC/ Chevy trucks or SUVs.

Did you ever change the transmission fluid and filter at regular scheduled intervals?
What did you use your truck to tow?

GM my whole like except when I bought a Dodge one time. Never had a problem with any trans ever in the GM's, However the dodge tranny went out 2 thousand miles after the warranty.

'93 chevy 1500 sold with 230k miles and original transmission
'94 chevy 1500 sold with 265k miles and original transmission
'97 Yukon sold with 160k miles and original transmission
Still have
'06 Tahoe with 220k miles and original transmission
'04 2500 hd duramax with 230k miles and original transmission
'05 2500 hd duramax with 200k miles and original transmission
'11 chevy 1500 with 100k miles and original transmission

All except the 2006 Tahoe have seen their fair share of towing use and all except the same Tahoe have been service per the recommendations of the manufacturer.

To be fair though we have owned GM, Ford, and Ram, and only one (a ford) has had a transmission problem, and it was some sensor replaced under warranty.

My 05 made it 315,000 on the original fluid towing every weekend. Never turned a wrench on this truck until 200,000 when a wheel bearing went out.

The guy who specializes in transmission in our shop sits around a lot. That's all I've got to say about transmission problems.

That is what I am looking to buy.